摘要:High grain number is positively correlated with grain yield in rice, but it is compromised because of poor filling of basal spikelets in dense panicle bearing numerous spikelets. The phenomenon that turns the basal spikelets of compact panicle sterile in rice is largely unknown. In order to understand the factor(s) that possibly determines such spikelet sterility in compact panicle cultivars, QTLs and candidate genes were identified for spikelet fertility and associated traits like panicle compactness, and ethylene production that significantly influences the grain filling using recombinant inbred lines developed from a cross between
indica rice cultivars, PDK Shriram (compact, high spikelet number) and Heera (lax, low spikelet number). Novel QTLs,
qSFP1.1,
qSFP3.1, and
qSFP6.1 for spikelet fertility percentage;
qIGS3.2 and
qIGS4.1 for panicle compactness; and
qETH1.2,
qETH3.1, and
qETH4.1 for ethylene production were consistently identified in both
kharif seasons of 2017 and 2018. The comparative expression analysis of candidate genes like
ERF3,
AP2-like ethylene-responsive transcription factor,
EREBP,
GBSS1, E3 ubiquitin-protein ligase
GW2, and LRR receptor-like serine/threonine-protein kinase
ERL1 associated with identified QTLs revealed their role in poor grain filling of basal spikelets in a dense panicle. These candidate genes thus could be important for improving grain filling in compact-panicle rice cultivars through biotechnological interventions.