Primary-tiller panicle number is critical to achieving high grain yields in machine-transplanted hybrid rice

Abstract Increasing rice production by using genetically improved rice cultivars and fertilizer application has been the main objective of rice farming. The double rice-cropping system has been an important rice production system in the middle and lower reaches of the Yangtze River in China since the 1950s. It is of great significance to determine whether hybrid vigor can make a substantial contribution to early- and late-season rice production, and how the heterosis expression of hybrid rice functions under different level of fertilization application. The objective of this study was to evaluate the grain yield and associated plant traits of popular hybrid and inbred rice varieties with large-scale promotion under conditions of customary (high) and combined (low) fertilization in the early and late seasons of 2017-18 in Changsha County, Hunan Province, central Southern China. We found that hybrid rice varieties displayed their respective advantages in the early- and late-rice seasons, but the advantages in their relative yield traits varied. The main advantages of early-season rice were effective panicle number per hill (EPN), 1000-grain weight (KGW), harvest index (HI), yield, and nitrogen use efficiency (NUE). Whereas in late-season rice, the major advantages were grain number per panicle (GNP), HI, yield, and NUE. The EPN was the main advantage of early-season hybrid rice with a short-growth period, and the GNP was the main advantage of late-season hybrid rice with a long-growth period. The main yield advantage of hybrid rice was stronger under combined (low) fertilization than under customary (high) fertilization. Hence, high yield can be achieved by selecting good hybrid rice varieties and by using combined fertilization (lower fertilizer use with higher efficiency). This work is contributive for rice growers, extension specialists, and fertilizer producers, as it provides data that can be used to maximize yields with reduced fertilizer and pesticide inputs.

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Integrated analysis of phenome, genome, and transcriptome of hybrid rice uncovered multiple heterosis-related loci for yield increase

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1610115113 ◽

2016 ◽

Vol 113 (41) ◽

pp. E6026-E6035 ◽

Cited By ~ 49

Author(s):

Dayong Li ◽

Zhiyuan Huang ◽

Shuhui Song ◽

Yeyun Xin ◽

Donghai Mao ◽

...

Keyword(s):

Candidate Genes ◽

Molecular Mechanisms ◽

Hybrid Rice ◽

Transcriptome Profiling ◽

Common Mechanism ◽

Integrated Analysis ◽

Dominant Form ◽

Yield Increase ◽

Great Yield ◽

Panicle Number

Hybrid rice is the dominant form of rice planted in China, and its use has extended worldwide since the 1970s. It offers great yield advantages and has contributed greatly to the world’s food security. However, the molecular mechanisms underlying heterosis have remained a mystery. In this study we integrated genetics and omics analyses to determine the candidate genes for yield heterosis in a model two-line rice hybrid system, Liang-you-pei 9 (LYP9) and its parents. Phenomics study revealed that the better parent heterosis (BPH) of yield in hybrid is not ascribed to BPH of all the yield components but is specific to the BPH of spikelet number per panicle (SPP) and paternal parent heterosis (PPH) of effective panicle number (EPN). Genetic analyses then identified multiple quantitative trait loci (QTLs) for these two components. Moreover, a number of differentially expressed genes and alleles in the hybrid were mapped by transcriptome profiling to the QTL regions as possible candidate genes. In parallel, a major QTL for yield heterosis, rice heterosis 8 (RH8), was found to be the DTH8/Ghd8/LHD1 gene. Based on the shared allelic heterozygosity of RH8 in many hybrid rice cultivars, a common mechanism for yield heterosis in the present commercial hybrid rice is proposed.

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Grain Yield Performance of Hybrid Rice in Multi-Environment Tests for Thirty-two Years in India

10.21203/rs.3.rs-122407/v1 ◽

2020 ◽

Author(s):

KALAMBUR MURALIDHARAN ◽

Gogineni S. V. Prasad ◽

Chilukuri S. Rao ◽

Ranganathan Srid ◽

Ebrahim A. Siddiq

Keyword(s):

Genetic Gain ◽

Crop Production ◽

Hybrid Rice ◽

Economic Value ◽

Test Duration ◽

Hybrid Seed Production ◽

Yield Data ◽

Grain Yields ◽

Limit Test ◽

Early Maturing

Abstract Background: Hybrid F1genotypes with higher yields or improvement in other traits of economic value due to heterosis as compared to inbred local check varieties (ILCV), are identified and released as hybrid commercial varieties. We analyzed the yield data of 2070 hybrid F1 genotypes with ILCV evaluated over 32 years (1988 to 2019) in 2376 multi-environment experiments executed at 102 locations in the irrigated ecosystem across India. Results: The genetic gain or loss in yield of hybrid F1 genotypes estimated over the test duration was non-significant. Hybrid F1 genotypes produced 10% more grains (728-2588 kg/ha) than ILCV in many experiments at several locations. Our analyses have established that grain yields of 7.0 to 7.9 t/ha, were harvested in hybrid F1 genotypes with early, mid-early and medium maturity duration, and in those with medium slender grains at many locations in 362 experiments. A higher level of rice productivity per day (62 to 63 kg/ha) was recorded with the early maturing and mid-early maturing hybrid F1 genotypes in these tests. The N requirement to produce 8 t/ha of hybrid rice grains was 15 kg N/t as compared with a minimum of 20 kg N/t used in China. Both the hybrids and inbreds in these experiments produced grain yields that were easily attained previously with high yielding (≥10 t/ha) commercial inbreds since 1968. Unless the attainable yields are reached in inbred checks with the proven appropriate crop production practices in an experiment, it is futile to estimate a genetic gain or loss for grain yields in new genotypes developed.Conclusions: Hybrid genotypes bred in India produced yields of 7 to 8 t/ha which matched with reports from China on hybrids and green super rice; these India-bred hybrids showed higher productivity per day and shorter maturity periods than super hybrids of China. Opportunities still exist to breed indica/japonica hybrids to obtain more heterotic early and mid-early maturing hybrids, and develop efficient agronomical practices to realize the potential advantages from hybrids. There is scope for breeders to limit test locations to represent specific target areas to avoid data loss. Focusing on removing obstacles in hybrid seed production is essential to exploit yield heterosis in hybrids, and to make hybrid rice technology profitable to farmers.

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Hybrid rice: Reproductive barrier

Nature China ◽

10.1038/nchina.2008.193 ◽

2008 ◽

Author(s):

Jane Qiu

Keyword(s):

Hybrid Rice ◽

Reproductive Barrier

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Phosphorus fertilization in inbred and hybrid rice

Dhaka University Journal of Biological Sciences ◽

10.3329/dujbs.v19i2.8962 ◽

1970 ◽

Vol 19 (2) ◽

pp. 181-187

Author(s):

MR Islam ◽

PK Saha ◽

SK Zaman ◽

MJ Uddin

Keyword(s):

Grain Yield ◽

Key Words ◽

Hybrid Rice ◽

Phosphorus Fertilization ◽

Phosphorus Fertilizer ◽

Yield Difference ◽

P Balance ◽

Rice Genotypes ◽

Boro Rice

Five phosphorus rates (0, 5, 10, 20 and 30 kg P/ha) were tested with four rice genotypes in Boro (BRRI dhan36, BRRI dhan45, EH1 and EH2) and T. Aman (BRRI dhan30, BRRI dhan49, EH1 and EH2) season. Phosphorus rates did not influence grain yield irrespective of varieties in T. Aman season while in Boro season P response was observed among the P rates. Application of P @ 10 kg/ha significantly increased the grain yield. But when P was applied @ 20 and 30 kg P/ha, the grain yield difference was not significant. The optimum and economic rate of P for T. Aman was 20 kg P/ha but in Boro rice the optimum and economic doses of P were 22 and 30 kg/ha, respectively. Hybrid entries (EH1 and EH2) used P more efficiently than inbred varieties. A negative P balance was observed up to 10 kg P/ha. Key words: Response; Phosphorus fertilizer; Inbred; Hybrid rice DOI: http://dx.doi.org/10.3329/dujbs.v19i2.8962 DUJBS 2010; 19(2): 181-187

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Heritability and Genetic Advance Estimation From Parental Lines of Hybrid Rice

International Journal of Scientific Research ◽

10.15373/22778179/july2014/5 ◽

2012 ◽

Vol 3 (7) ◽

pp. 11-13

Author(s):

Arpita Shrivastava ◽

◽

D. K. Mishra D. K. Mishra ◽

G. K. Koutu G. K. Koutu ◽

S. K. Singh S. K. Singh

Keyword(s):

Hybrid Rice ◽

Genetic Advance ◽

Parental Lines

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QUALITATIVE STABILITY OF WINTER WHEAT VARIETIES AT DIFFERENT LOCATIONS

Acta Agronomica Hungarica ◽

10.1556/aagr.48.2000.2.10 ◽

2000 ◽

Vol 48 (2) ◽

pp. 191-195

Author(s):

C. Kondora ◽

M. Szabó ◽

A. Máté ◽

G. Szabó

Keyword(s):

Quality Control ◽

Winter Wheat ◽

Evaluation Method ◽

Wheat Varieties ◽

Local Conditions ◽

Grain Yields ◽

Baking Quality ◽

Small Plot ◽

High Yielding Varieties ◽

Winter Wheat Varieties

Owing to the significant differences in the adaptability of state-registered varieties, those which can adapt well to the local conditions should be given preference. There are several high-yielding varieties available in Hungary with excellent agronomic properties, good adaptability and satisfactory baking quality. This study was conducted to analyse the adaptability of 34 state-registered winter wheat varieties tested in the small plot trials of the National Institute for Agricultural Quality Control (NIAQC) at 5–9 locations between 1994 and 1997 based on their gluten quantity and farinographic index. For the comparison of the varieties the evaluation method of Eberhart and Russell (1966) was applied as modified by Bedő and Balla (1977). The qualitative stability and adaptability values of the varieties differ from the adaptability and stability values calculated from the grain yields. Some winter wheat varieties have good qualitative adaptability and stability, while others have special adaptability and poor qualitative stability, but the majority of the varieties do not belong to these groups.

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