Genetic Behavior and Cluster Analysis of Some Floral Traits Affecting Cross Breeding in The Production of Hybrid Rice Seed

Abstract

Genetic development of improved genotypes with good floral charactaristics is the an important approach in the production of hybrid rice seed. Ten rice parental lines where four of them have cytoplasmic male sterility while the other six use restorer. These ling were crossed to obtain 24 hybrid combinations, through a factorial mating design. The parental lines and their 24 F 1 hybrids were grown in randomized complete blocks design with three replications at Rice Research and Training Center Farm, Sakha Kafr El-Sheikh, Egypt during the two seasons of 2011 and 2012. Data were recorded on six floral traits viz., anther length, anther breadth, number of pollen grains anther -1 , stigma length, stigma breadth and glume opening angle. The analysis of variance of all genotypes revealed highly significant mean squares for all studied traits, suggesting the presence of genetic differences among the genotypes used in this study. The magnitude of genetic parameters indicated that the additive variance (σ 2 A) for anther length, number of pollen grains anther -1 , glume opening angle traits were higher than the corresponding nonadditive variance including dominant (σ 2 D). These results indicated that these traits were largely governed by additive gene action. Thus, the estimated values of heritability in broad sense were higher than heritability in narrow sense for all the studied floral traits. A major part of the total phenotypic variance was due to non-additive including dominance genetic variances for all floral traits. The maternal effects were affective in stigma breadth (37.25%) and glume opening angle (70.15%). The contribution of maternal and paternal interactions (Line x Tester) were found to be vital for anther breadth (57.86%) and stigma breadth (37.43%). The ten parental lines were distinctly classified into two major clusters (below 1200 Euclidean distance) according to the similarity diagram.

Superiority for Agronomic and Yield Traits in Hybrid Rice Under Normal and Saline Conditions

“…The hybrids Pusa 3A/GZ6296R; Pusa 6A/Giza 182R; Pusa 6A/GZ6296R; IR58025A/GZ6296R; IR69625A/Gz6296R; IR70368A/ Gz6296R and IR68902A/Gz6296R were the earliest flower with significant negative superiority over check inbred and hybrid variety, Giza 178 and EHR1, respectively under both normal and saline soil conditions. These findings indicated that heterosis effects can be used to get earliness in rice hybrids (El-Mowafi, 2001;El-Mowafi et al, 2005;El-Mowafi et al, 2015 andAbd El-Hadi et al, 2016).…”

“…Among hybrids, the estimates of heterosis ranged from 6.643 to 31.511% under normal soil condition for the hybrids IR69625A/PR3 and Pusa 6A/Giza 178R, respectively. On the other hand, the superiority over hybrid check variety EHR1 under saline soil condition ranged from 5.187 to 23.401% for the hybrids IR69625A/PR1 and Pusa 3A/PR3, respectively (El-Mowafi et al, 2015;Veeresha et al, 2015 andAbd El-Hadi et al, 2016).…”

“…Only the hybrid rice combination IR69625A/GZ5121R gave a significantly positive superiority over the best hybrid check variety EHR1 with a value of 1.83% under saline soil condition. (El-Mowafi, 1994;Abd El-Hadi and El-Mowafi, 2005;Soltan, 2007;Vanisree et al, 2011;Zayed et al, 2015 andAbd El-Hadi et al, 2016).…”