Current Status and Future Prospects of Head Rice Yield

Abstract

Global warming poses a serious threat to food security because of its impacts on thermosensitive food crop production. Rice is of paramount significance due to the world’s three-billion-population dependence on it as a staple food. It is well established that the high temperatures at day or night times during the grain-filling period can reduce rice grain yield, although the intriguing impact of high temperatures on head rice yields (HRY) is poorly discussed. This is because high and stable HRY is vital to meet the demand for rice grain, which is a staple food for many developing and developed nations. Hence, identifying the novel heat-tolerant rice germplasm with higher head rice yields may help mitigate a critical problem threatening global food security resulting from climate change. This review addresses the key factors, including pre-and-post-harvest scenarios related to overall reductions in the HRY and how grain molecular composition can play a significant role in determining head rice yields. Moreover, the underlying genetics of head rice is discussed as and possible mechanism to breach the complexity of HRY before identifying the key alleles and genomic regions related to the reduction in the HRY. Future research should focus on understanding the mechanisms of tolerating heat stress in rice by combining modern statistical, physiological, and molecular techniques to increase HRY. This may include high-throughput phenotyping techniques, mapping quantitative loci affecting HRY loss processes and genomic prediction using a broad wild and cultivated rice germplasm.

Multi-model genome-wide association studies for appearance quality in rice

“…In addition, HRR (%) and PGC (%) had a very weak positive correlation with a Pearson correlation coefficient (PCC) of 0.03, which was also consistent with current correlation studies and BLUP estimates ( Sanchez et al., 2023 ; Nirmaladevi et al., 2015 ; Vemireddy et al., 2015 ; Cruz et al., 2021 ; Ali et al., 2023 ). Broad-sense heritability (H 2 ) estimates were high for HRR (%) (0.99) and PGC (%) (0.98) which was consistent with similar studies ( Sanchez et al., 2023 ; Ali et al., 2023 ). The considerably low H 2 for grain aroma (0.28) suggested that its environmental influence was attributed to the experimental conditions, as pointed out in an earlier study ( Vemireddy et al., 2015 ).…”

A bioeconomic quantitative genetic model for assessing milling yields in rice

“…The kinship matrix or G-matrix was developed using the 1,512 DArTseq SNP markers mapped using the 282 RILs using the GCTA software (Yang et al, 2011) with its default parameters. 3 Numbers of all DArTseq™ markers residing in each linkage group 4 Total length of chromosome measured in centimorgan (cM) of each linkage group 5 Markers coverage on each chromosome in mega-base pairs (Mb).…”

“…Reduction in HRY following heat stress events is generally attributed to increased ssuring or grain cracking, which may be caused by grain chalkiness contributing to structural weakness (Cooper et al, 2006), but contradictory ndings were found (Ali et al, 2023). Also, it was recently found that grain breakage during the de-husking or polishing milling operations was also genotype-dependent (Ali et al 2019b).…”

“…1 Chromosome number(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) representing original diploid rice chromosome2 Number of locally constructed genetic linkage groups (LGs: 1-16) derived from DArTseq™ data using two software packages; Join Map (4.10 Kyazma) and (R Package)…”

“…The nomenclature of detected QTLs follows that ofMcCouch et al (1997) with q (QTL) + trait name + chromosome number + the number of each QTL on the respective chromosome 4. Left, right: markers bordering the QTL interval.…”