Characteristics and coordination of source-sink relationships in super hybrid rice

Pu Bai; Ruoqi Bai; Yuxue Jin

doi:10.1515/biol-2016-0061

Artikel Open Access

Characteristics and coordination of source-sink relationships in super hybrid rice

Pu Bai , Ruoqi Bai und Yuxue Jin

Veröffentlicht/Copyright: 15. Dezember 2016

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Abstract

This paper discusses the characteristics of source and sink for super hybrid rice and how to coordinate its source-sink relationships for high-yielding cultivation. It is known that super hybrid rice possesses a higher net photosynthetic rate than non-hybrid rice because of its higher grain-leaf area ratio, better stornata traits and less midday depression. However, the sink of super hybrid rice remains large due to its large and numerous spikelets. Furthermore, the relocation of assimilates is smooth in super hybrid rice because of its well-developed vascular structure. However, due to the very large sink of super hybrid rice, it is relatively inefficient in supplying of assimilate products to spikelets, in particular to inferior spikelets. Therefore, reducing the discrepancy between source and sink in super hybrid rice is essential for developing high-yielding cultivation. This can only be achieved by planting cultivars adapted for local environments, raising strong seedling, setting up populations with a high photosynthetic efficiency for increasing the supply of source, and improving the field management in filling stages to the duration of supply of photosynthate to grains.

Keywords: Characteristics; coordination; source-sink relationships; super hybrid rice; sink size; photosynthesis

1 Introduction

Since Mason M. L. and Maskell E. J. put forward the theory of source-sink relationships on crops in 1928, ongoing research has guided the breeding and high-yielding cultivation of rice [1–2]. China has developed new rice varieties with inter-subspecies heterosis by utilizing wide compatibility genes since the mid-1980s. However, nitial breeding varieties were not applied because of their lower grain plumpness degree and seed setting rates, which resulted from their large sinks, relatively insufficient resources and not smoothly transporting assimilate products during their grain filling stage [3–4]. Zhou Kaida advanced the concept of “heavy panicle hybrid rice” in 1995 [5], and Yuan Longping launched the concept of “new plant type of hybrid rice “with “long, straight, narrow, concave, thicker, low barycenter” in 1997 [6]. These two concepts are combined in the ideal plant type and the utilization of inter-subspecies heterosis, by which breeders in China have successfully bred excellent 118 super rice up to April, 2015, such as Liangyoupeijiu, Zhongzheyou 1, Yongyou 12, Yongyou 15. These combinations produce large spikes, high yields with good quality, a strong resistance to major diseases, higher grain plumpness, and seed setting rate, due to improvements in their source-sink relationships. These varieties are referred to as super hybrid rice [7–10]. At present, these hybrids have been widely planted and some have become head cultivars in some areas such as Wenzhou, Zhejiang Province, China [11]. The authors of this current study started research on the characteristics and high-yielding cultivation techniques of super hybrid rice from 1998, when the pioneer super hybrid rice strains Liangyoupeijiu and Xieyou 9308 were successfully bred and harvested [12]. Current cultivating practices show that the balance between source and sink in super hybrid rice remains uneven. This symposium discusses the source-sink relationships, the characteristics of source, sink, flow and grain filling and how to coordinate the source-sink contradictions in super hybrid rice.

2 The characteristics of source-sink relation and grain filling in super hybrid rice

2.1 The characteristics of source

Compared to ordinary hybrid rice, the supply and utilization of source in super hybrid rice combinations have been improved significantly [13]. Super hybrid rice has more green organs (leaves, sheaths) with a high photosynthetic efficiency and the accumulation of dry matter, especially in its late growth stage [14–15]. Wang Longfu reported that a super hybrid rice Liangyoupeijiu absorbs and transforms more light energy into chemical energy than both of its parent strains, Pei’ai 64S and Indica 9311 [16]. According to Ning Shuju [17] , the net photosynthetic rate in the flag leaf of the super rice Liangyoupeijiu and Dyou527 is significantly higher than those of conventional hybrid rice after heading, which is due to the increase of Rubisco activity and chlorophyll content in their flag leaf as well as excellent stomatal traits. Super hybrid rice also exhibits lower midday photoinhibition and a longer duration of high-value photosynthesis [18,19]. The increase of the grain-leaf ratio in super hybrid rice can also significantly improves the photosynthetic efficiency of its leaves [20]. According to Guo Zhangwei, the photochemical activities of the flag leaf sheathes in super hybrid rice Liangyoupeijiu are stronger than its male parent 9311, female parent Pei’ai 64S, and the ordinary hybrid rice cultivar Shanyou 63 [21]. The tillering ability of super hybrid rice is lower than that of ordinary hybrid rice because of its weaker apical dominance, which results in less ineffective tillering, a better population quality in the field, higher economic factors and more effective utilization of assimilates. Furthermore, both expansion of leaf area and extension of the grain filling stage in super hybrid rice also increase the supply of photosynthetic resources. Due to its significant increase of spikelets per panicle, each of the spikelet in super hybrid rice is allocated relatively lower photosynthetic products. Thus, improving the supply of source remains a major hurdle for the ongoing improvement of super hybrid rice.

2.2 The characteristics of sink

Super hybrid rice develops panicles with more grain For example, Liangyoupeijiu planted as single crop rice in Wenzhou has more than 200 grains per panicle and as a double late rice has more than 180 grains per panicle, which is more 30% than an ordinary hybrid rice combination Shanyou 63 [22]. Under the same cultivation conditions, the single panicle weight of super hybrid rice is 10 to 15% more than ordinary hybrid rice. The increase of spikelets in super hybrid rice is mainly due to a significant increase in its secondary branches and spikelets per secondary branch. However, most spikelets in secondary branches bloom later and belong to inferior spikelets [23]. It has been reported that an increase of the sink in rice has a positive effect on the accumulation of assimilate products in grains by improving leaf photosynthetic rate as well as accelerating transporting and transformation of assimilation products [24]. Super hybrid rice possesses thick stems, short basal internodes, and leaf sheaths tightly wrapped the wall of stem, so that they can support the greater grain weight. In addition, less productive tillers can obtain high yields because of increases of the single spikelet output in super rice. Panicle with large spikelets require enough supply of assimilation products for promoting their seed setting rate and grain plumpness degree [25]. Therefore, it is necessary to adopt some reasonable cultivating measures to promote source, smooth flow, and increase grain wright for steadily achieving high-yielding cultivating in super rice.

2.3 The characteristics of flow

The ability to transport photosynthetic products to kernels during the filling stage markedly affects the yield of rice, and the vascular bundle of the first internode is the vital structure to determine whether the “flow” is smooth, because it is the channel to transport mineral nutrition and assimilation products [26]. According to Ma Jun [27] , super hybrid rice plants have more vascular bundles with larger areas of each vascular bundle, more total vascular bundles, and greater total phloem and total xylem in the first internode than the ordinary hybrid rice, Shanyou 63. The vascular bundle has a similar spikelet number load and sink load in super hybrid rice and Shanyou 63, though the former has many more spikelets than the latter. The vascular tissues in super hybrid rice panicles reduce the spikelet number load and sink load. Therefore, the problem to be solved to avoid poor assimilate during grain filling in super hybrid rice cultivars with inter-subspecies heterosis involves both genetic and physical mechanisms [28,29]. Some super hybrid cultivars such as Zhongzheyou 1, Yongyoul2, Yongyou 15, Dyou 527 and Liangyoupeijiu have been planted in Wenzhou, China. They have not only large panicles but also a higher seed setting rate and grain plumpness. The relocation of assimilates from the stem and sheath is close to 50% at physiological maturity, which shows that the flow is very smooth [30].

2.4 The characteristics of filling

The rate of grain filling of spikelets varies with panicle position. Generally, the superior spikelets fill earlier and faster than the inferior ones, and in addition the inferior ones show an obvious diapause phenomenon in the early period of heading. This phenomenon is referred to differently by researchers, including “asynchronous filling” [31] , “two-step filling” [32] , and apical-grain superiority” [33]. This paper found significant differences in grain filling characteristics between super hybrid rice (Liangyoupeijiu) and a large panicle type ordinary hybrid rice (Xieyou 46) (Figure 1). The superior spikelets of Xieyou 46 quickly fill to full grain during the initial filling stage, after which the grain weight increases little. Figure 1 presents a line with the same slope in the first stage of grain filling, followed by another line approximately parallel to abscissa (tme), with an obvious break point between two lines. However, the superior spikelets of Liangyoupeijiu rapidly increase in grain weight during the early stage of grain filling, then the rapid growth slows as maximum grain weight is neared. This is seen with the smaller arc-shaped curve during grain filling. The weight of inferior spikelets of the two cultivars increases much more slowly than that of superior spikelets, and that of Liangyoupeijiu is slower than that of Xieyou 46. The slope of grain filling of inferior spikelets in Liangyoupeijiu is less than that of Xieyou 46, which indicates that there is still insufficient supply of assimilate products in the inferior spikelets of super hybrid rice. Other researchers also reported similar results [34]. Therefore, it is crucial to improving the seed setting rate and the grain plumpness degree of inferior spikelets for super hybrid rice high-yielding cultivars.

Figure 1

Comparison of grain filling of super hybrid rice cultivar (Liangyoupeijiou) and conventional hybrid rice cultivar (Xieyou 46) in superior (1) and inferior (2) grains.

3 Coordinating the relationship between source and sink in super rice

3.1 Planting appropriate cultivars

Super hybrid rice cultivars exhibit different environmental adaptability [35]. Gu Wei [36] reported that there are differences in the ecological characteristics of Eteyoul07 planted in Nanjing, Jiangsu Province, China and Taoyuan Town, Yongsheng County, Yunnan Province, China. The super hybrid rice Teyoul75 planted in Taoyuan Town once set a world record of rice yield at that time, but similar production levels have been recorded in Wenzhou. Liangyoupeijiu planted in the plains and low mountains of Wenzhou, China has an outstanding performance, but it is not adaptable to high mountainous areas because of its susceptibility to the false smut occurring in Wenzhou [37]. Therefore, in order to fully take advantage of the high yield potential of super hybrid and reducing the discrepancy between source and sink, it is important to select excellent cultivars of super hybrid rice and study the characteristics of cultivation such as sensitivity to light, temperature, and feasible date of sowing and transplanting, as better light and temperature environments are required during the filling stage. For example, the growth period of Liangyoupeijiu is too long for its cultivation as double late rice in Wenzhou, but it is still an appropriate cultivar if sown before June 20, because of its greater thermo sensitivity. Therefore, it has been planted widely in Wenzhou. At present, other excellent cultivars such as Zhongzheyou8, Yongyou9 and Zhongzheyoul have been widely planted scale in Wenzhou, as they are the main cultivars with disease resistance, high yield, and high quality [38].

3.2 Raising robust seedlings

The robustness of seedlings and early development of tillers after transplantation in paddy fields forms the basis for coordinating the source-sink relationship in super hybrid rice [39]. Stronger seedlings have more tillers and higher root activity, so the plants quickly turn green and develop tillers early after transplantation. The panicles developed from early emergence tillers or nursery field tillers have well-developed vascular tissues, which improves the transportation of photosynthetic products to grains and increase their source capacity due to higher leaf area and longer vegetable growth duration. Most planting techniques aim to raise stronger seedling by precisely controlling sow seed rate, fertilizer and water management, and chemically regulating the height of seedlings. It is more difficult to raise stronger seedlings for super hybrid double late rice, because of the longer required nursery period with strong light and high temperatures. Thin sowing is an important measure to raise stronger seedling for double late rice. In order to control height, promote early tillering, seeds are usually soaked with 50 to 100mg/L liquid uniconazole, and then planted at 75-105 kg/ha. [40]. In the basal fertilizer applied to seedbeds, nitrogen fertilizers should be decreased while phosphorous and potassium fertilizers increased. Moreover, N fertilizers are usually not applied during the nursery period, except a small amount 3 days before transplanting in double late rice. In Wenzhou, planting super hybrid rice as a single crop can slightly increase the seeding rate when sown between late May and early June, using semi-dry cultivation with a seedling age of about 35 days to ensure enough time for the growth of preceding crops [41].

3.3 Setting up populations with high photo-synthetic efficiency

It is essential to set up populations with high photosynthetic efficiency for reduce the discrepancy between source and sink in super hybrid rice [40]. It has been shown that the population with high spike rate on the basis of a certain number of spikes is a high photosynthetic efficiency population [42]. Population with high photosynthetic efficiency possesses high-yielding potential due to several factors including coordination between the the individual and population levels, high light transmittance through leaf layers, organized leaf canopies, low extinction coefficient, high grain-leaf ratio, high photosynthetic efficiency and net assimilation rates [43]. The early and middle tiller stages are the important periods to set up populations with high photosynthetic efficiency. Maximizing the number of effective tillers requires fertilizer made up of nitrogen and basic manure, as well as early dry-cultivation with multiple light sources [44].

3.4 Strengthening field management in the mid-late stage

Effective field management is required to maintain a source and sink balance for high-production growth in the mid and late tiller stages. [45]. This include applying a fertilizer of 45 kg/ha urea and 75 kg/ha potassium chloride during spikelet development, but not during spikelet promotion as this will cause degeneration of the plant structures. [46]. The application of nitrogen in spikelet-developing fertilizers can increase nitrogen content, increase photosynthetic efficiency, and reduce the degradation of spikelets. Application of potassium in spikelet developing fertilizers can promote the synthesis and transfer carbohydrates to the grains, increasing seed setting rate and grain plumpness degree [47]. Exogenous hormones can also regulate the filling of super hybrid rice [48]. Spraying potassium dihydrogen phosphate and the special exogenous hormones Lilibao (meaning every grain will be filled, a plant growth substance including GA 3 and PP 333) at initial heading stage, can promote the heading, increase nutrition and regulate the relationship between inferior spikelets and superior spikelets, increasing seed setting rate and grain weight [49]. Crops should be irrigated with shallow water at the booting stage, paddy fields exposed at the heading stage, wet and dry cultivation alternated at the premature stage to increasing leaf photosynthetic efficiency, and delaying leaf senescence of super rice, resulting in greater transportation of carbohydrates to the grains [50–51].

Acknowledgments

The authors are deeply grateful to Bureau of Science and Technology in Zhengjiang (No.2012D70086) and Bureau of Science and Technology in Wenzhou (No. N20160016) for its financial.

Conflict of Interests: The authors declare that there is no conflict of interests regarding the publication of this paper.

References

1 Fang W., Guoping Z, Pu B., Achievement and prospects of research on evaluation of the relationship between source and sink in rice, Chinese J. Rice Sci., 2005,19, 556-560.Suche in Google Scholar

2 Dahai S., Yuanjing L., Guang L., Advances and applications of or research on source-sink relations of rice, J. Northeast Agri. Uni., 2009, 40,117-122.Suche in Google Scholar

3 Jinagchang Y., Wenfu Z., Yuqing W., Lijun L, Qinshen Z., Source-sink characteristics and the translocation of assimilates in new plant type and japonica/indica hybrid rice, Sci. Agri. Sin., 2001, 34, 511-518.Suche in Google Scholar

4 Jinagchang Y., Jianhua Z., Grain-filling problem in super rice, J Exp. Bot., 2010, 61,1-5.10.1093/jxb/erp348Suche in Google Scholar PubMed

5 Kaida Z.,Yongqin M.,, Taiuqin L. Maoshong S., The breeding of sunspecific heavy ear hybrid rice-exploration about super-high yield breeding of hybrid rice, J. Agri. Uni. Shich.,1995,13, 403-407.Suche in Google Scholar

6 Longpin Y., The Super-high yield breeding of hybrid rice, Hybrid Rice, 1997, 6,1-6.Suche in Google Scholar

7 Shihua C, Innovation and development of rice breeding of super high yield in China. J. Shenyang Agri. Uni., 2007, 38, 647-651.Suche in Google Scholar

8 Loida M., Perez, Edilberto D., Redoña, Casiana M., Introgression of Xa4, Xa7 and Xa21 for resistance to bacterial blight in thermosensitive genetic male sterile rice (Oryza sativa L.) for the development of two-line hybrids, Euphytica, 2008,164, 627-636.10.1007/s10681-008-9653-1Suche in Google Scholar

9 Hao C., Yongjun L., Qifa Z., Review and prospect of transgenic’rice research, Chinese Sci. Bull., 2009, 54, 4049-4068.10.1007/s11434-009-0645-xSuche in Google Scholar

10 Yongshu L., Xiaode Z., Zhiqing G. Zechuan L., Zhanlie Y., Mapping of QTLs associated with important agronomic traits using three populations derived from a super hybrid rice Xieyou9308, Euphytica, 2001,184,1-13.Suche in Google Scholar

11 Pai B., Pengxi W., Yuanhuei W., Kaizhan T., Practice of successful extension of super rice in Wenzhou, Zhejiang, Hybrid Rice, 2006, 21, 54-56.Suche in Google Scholar

12 Pu B., Application and efficiency of ecological and highly effective cultural technique in hybrid rice, Res. Agri. Mod., 2010, 31, 343-346.Suche in Google Scholar

13 Shihua C., Liyong C., Senguang C. Defeng Z., Xi W., Saokai M., Conception of late-stage vigor super hybrid rice and its biological significance, Chinese J. Rice Sci., 2005,19, 280-284.Suche in Google Scholar

14 Yinhua Z., Linjing C., Jianse H., Lisan Q., Liuqiang W., Renfu W., Characteristics of chlorophyll fluorescence and antioxidative system in super-hybrid rice and its parental cultivars under chilling stress, Biol. Plant, 2010, 54,164-168.10.1007/s10535-010-0027-xSuche in Google Scholar

15 Peng W., Guilin Z., Kehuei C., Li Z.H., Yu S.B., Clustered QTL for source leaf size and yield traits in rice (Oryza sativa L.), Mol. Breed., 2010,29, 237-243.10.1007/s11032-010-9529-7Suche in Google Scholar

16 Longfu W., Yuhua Z., Demao J., Characteristics of photoinhibition and early characteristics of chotoinhibition and early aging in super-hybrid rice (Oryza sativa L.) “Liangyoupeijiu” and it’s parents at late development stage, Acta Agron. Sin., 2004,4,296-300.Suche in Google Scholar

17 Shuju N., Xiaofei C., Xiang X.L., Studied on physiology bases of grain filling for “Liangyoupeijiu” at the late development stage, Chinese Agri. Sci. Bull., 2009, 25, 211-217.Suche in Google Scholar

18 Qian W., Changmei L., Qida Z., Midday photoinhibition of two newly developed super-rice hybrids. Phtosynth, 2005, 43, 277-281.10.1007/s11099-005-0045-7Suche in Google Scholar

19 Kumagai E., Araki T., Uneo O.,. Effect of nitrogen-deficiency on midday photoinhibition in flag leaves of different rice(Oryza sativa L.)cultivars, Photosynthesis, 2009,47, 241-246.10.1007/s11099-009-0038-zSuche in Google Scholar

20 Qihong L., Jiangchang Y., Studies on “grain-leaf ratio” of population and cultural approaches of high yield in rice plants, Sci. Agri. Sin.,1986, 3, 1-8.Suche in Google Scholar

21 Zhaowu G., Langtao X., Preliminary study on photochemical activities in chloroplasts of flag leaf sheathes for super hybrid rice Liangyoupeijiu, Chinese J. Rice Sci., 2007, 4, 379-385.Suche in Google Scholar

22 Pu B., Pengxi W., Xufeng Z., Yuanhuei W., The high-yielding cultural techniques for Liangyoupeijiu grown as the second crop in double rice cropping system, Hybrid Rice, 2002,17, 31-32.Suche in Google Scholar

23 Wenge W., Hongcheng Z., Guicheng W., Chaoqun Q., Yinfeng Q., Ye C, Jun X., Qingen D., Ke X., Preliminary study on super rice population sink characters, Sci. Agri. Sin.,2007,40, 250-257.Suche in Google Scholar

24 Yin S., Guiliang Z., Wenbang T., Yinhuei X., Huabin D.,Xuntang Z., Liyun C., Source-sink characteristic of super-high-yield hybrid rice combinations C Liangyou 396 and C Liangyou 87, Hybrid Rice, 2010, 25,110-115.Suche in Google Scholar

25 Guo feng L., Peng S., Xizhi C., Studies on the relationship between grain sink activity of Japonica/lndica hybrid rice and its grain filling, Acta Bot. Boreali-occidental. Sin., 2002, 20, 179-186.Suche in Google Scholar

26 Ke C., Song P., Yun X., shao Y., Chang X., Qu Z., Molecular dissection of the genetic relationships of source, sink and transport tissue with yield traits in rice, TAG Theor. App. Genet., 2003,106,4,649-658.10.1007/s00122-002-1113-zSuche in Google Scholar PubMed

27 Jun M., Kaida Z., The relations between panicle characters of intersubspecific heavy panicle hybrid rice and vascular bundles in neck-panicle, Southwest China J. Agri. Sci., 2001,14,1-5.Suche in Google Scholar

28 Buhong Z., yINGE J., Xinhong C., Jiangchang Y., Qingsen Z. Hongxi Z., Characteristics of vascular bundles of peduncle and grain-filling in two-line hybrid rice, J. Shanghai Jiaotong Univ., 2004,22,181-184.Suche in Google Scholar

29 Huaju C., Shujen W., Molecular regulation of sink-source transition in rice leaf sheaths during the heading period, Acta Physiol. Plant., 2008, 30, 639-649.10.1007/s11738-008-0160-8Suche in Google Scholar

30 Pu B., Pengxi W., High-yielding cultural techniques for hybrid rice Xieyou9308, Hybrid Rice, 2000, 15, 36-37.Suche in Google Scholar

30 Zifeng G., Qingsen Z., Xianzhu C, Studies on the grain ripening rate of rice—the relationship between the accumulation of dry weight in vigorous and weak spikelets and the distribution of sterile, abortive kernel, Sci. Agric. Sin., 1981, 7, 38-43.Suche in Google Scholar

31 Jun M., Kaida Z., Wenbo M.,Xinde W., The characteristics of vascular bundles in the first internode and grain-filling of heavy panicle hybrid rice, Sci. Agri. Sin., 2002, 35, 576-579.Suche in Google Scholar

32 Guohuei M., Studies on the theory of two-step-filling of indica rice cultivars (Oryza sativa), Chinese J. Rice Sci., 1996,10, 153-156.Suche in Google Scholar

33 Xi W., Longxing T., Rengshen X. Apical-grain superiority in hybrid rice, Acta Agron. Sin., 2001, 27, 980-985.Suche in Google Scholar

34 Jiangchang Y., Mechanism and regulation in the filling of Inferior spikelets of rice, Acta Agron. Sin., 2010, 36, 2011-2019.Suche in Google Scholar

35 Sheng C., Furun Z., Zhong zan P., Characterization of high-yield performance as affected by genotype and environment in rice, J. Zhejiang Uni. Sci. B, 2008, 9, 363-370.10.1631/jzus.B0710603Suche in Google Scholar PubMed PubMed Central

36 Wei G., Ganghua L., Chongdang Y., Shaohua W., Qihong L., Yangfang D., Studies on ecological traits of super rice in special eco-site, J. Nanjing Agri. Uni., 2009, 32,1-6.Suche in Google Scholar

37 Pu Bai.„ Yuanhuei W., Xiong X., Kaizhan T., Pengxi W., Jie Y., Studies on full heading time and optimized sowing dates of hybrid rice Liangyoupeijiu, Acta Agri. Zhejiangen, 2006,18, 146-150.Suche in Google Scholar

38 Pu B., The new technologies of planting in rural area, Beijing, China Agri. Press, 2001,1-5.Suche in Google Scholar

39 Pu B., Anbo H.,Likuei X., Studies on effect of controlling height of seedling and promoting tillering for the late hybrid rice after soaking seed by Uniconazole, Hybrid Rice, 1995,11, 25-28.Suche in Google Scholar

40 Wu L., Qiang K., Xiangru T., Guoxi L., Hua T., Meiyang M., Studies on cultivation techniques characterized by enhancing source, activating sink and improving quality for double-cropping super rice, Hybrid Rice, 2010, 25, 73-77.Suche in Google Scholar

41 Pu B., The cultivation environment of crop, Beijing, China Environ. Sci. Press, 2003,1, 30-34.Suche in Google Scholar

42 Abha M., Vilas M. S., Rice root growth and physiological responses to SRI water management and implications for crop productivity, Paddy Water Environ., 2011, 9, 41-52.10.1007/s10333-010-0240-4Suche in Google Scholar

43 Jiangming Z., Haobo Y., Hepeng Z., Effects of different nutrient levels in different fertility soils on super rice yields and nutrient use efficiency, Acta Agri. Boreali-Sini., 2008, 23, 267-273.Suche in Google Scholar

44 Xinbei C., Mende R., Ximei X., Efects of nitrogen application rate on yield formation of super rice Youming 86 and absorption of N,P and K, J. Yiehun College, 2010, 26, 87-88,129.Suche in Google Scholar

45 Pu B., Xiong X., Kaizhan T., The non-polluted and high-efficient cultural techniques for a new inter-subspecific hybrid rice combination “Yongyou6”, Acta Agri. Jiangxi, 2007,19, 31-32.Suche in Google Scholar

46 Balkhair K. S., Ashraf M. A., Field accumulation risks of heavy metals in a soil and vegetable crop irrigated with sewage water in western region of Saudi Arabia, Saudi J. Biol. Sci., 2016, 23, S32-44.10.1016/j.sjbs.2015.09.023Suche in Google Scholar PubMed PubMed Central

47 Majid G., Javid A.S., Seyed A., Mohammad M.S., et al., Effect of the exogenous application of auxin and cytokinin on carbohydrate accumulation in grains of rice under salt sress, Plant Growth Regulation, 2011, 65, 305-313.10.1007/s10725-011-9602-1Suche in Google Scholar

48 Longxing T., Xiaolin Huang., Xi W., Meiyu Y., Biological effects of lilibao on rice plant. Chinese J. Rice Sci., 2000,14, 93-97.Suche in Google Scholar

49 Changming X., Huayuan H, Yenjun T., Chinese super hybrid rice breeding and its cultivation techniques, Hunan Agri. Sci., 2009,2,46-50.Suche in Google Scholar

50 Pu B., Guoping Z., Wei Z., Ruoqi B., Chunquan Z., Huajin. L., Study on techniques of mitigating GHG emissions and increasing carbon sink in paddy field, Acta Agricult. Shanghai, 2015, 31 (2),131-136.Suche in Google Scholar

51 Wei W., Baoluo M., Norman U., A review of the system of rice intensification in China, Plant Soil, 2015, 393, 361-381.10.1007/s11104-015-2440-6Suche in Google Scholar

Received: 2016-2-4

Accepted: 2016-8-21

Published Online: 2016-12-15

Published in Print: 2016-1-1

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