Abstract:

Panicle exclosure in CMS line is highly correlated with outcrossing rate of CMS in hybrid rice seed production. Panicle enclosure is occurred when flag leaf sheath length exceeds the uppermost internode length. In order to improve panicle exertion, it is necessary to understand the genetic mechanism of flag leaf sheath length, the uppermost internode length, and panicle enclosure. Under 3 different growing environments, the experiment was conducted using 98 backcross inbred lines (BILs) derived from a backcross of Nipponbare (japonica) / Kasalath (indica) // Nipponbare by the single seed descent methods. At 5% of genome-wide type I error, we detected QTLs of the 3 traits by composite interval mapping method. The results showed that 3 QTLs for flag leaf sheath length were detected totally, which were located on chromosome 1, 3, 4, and explained 12.83%–18.5% of observed phenotypic variance. The qFLL-1 was detected in 3 environments, its positive allele was from Nipponbare, qFLL-3, qFLL-4 were detected in single environment, their positive alleles were from Kasalath. For the uppermost internode length, 3 QTLs were detected on chromosome 1, 3, 6, and explained 5.64%–14.18% of observed phenotypic variance. The qUIL-6 was detected in all 3 environments, its positive allele from Nipponbare. The other 2 QTLs were detected in 2 of the environments, and Kasalath carried positive allele. Four QTLs for panicle enclosure length were detected on chromosome 1, 3, 5, 10, explained 6.8%–17.76% of observed phenotypic variance. The qPEL-10 was detected in all 3 environments. qPEL-5 was detected in 2 of the environments. Positive alleles of qPEL-10 and qPEL-5 were from Nipponbare. The other 2 QTLs were detected only in single environment, and their positive allele came from Kasalath.

Key words: Rice, Growing environment, Panicle exsertion-related traits, Quantitative trait locus mapping