Studies of genetics of yield and yield component characters in F2 and F3 generations of rice (Oryza sativa L.)

Abstract

Three parents with three different durations were crossed in full diallel fashion. The resultant six hybrids were selfed along with their three parents to get six F 2 's. The F 2 's were selfed to obtain six F 3 's. The aforementioned five generations of the six crosses were studied for days to flowering, number of productive tillers per plant, number of filled grains per panicle, 100 seed weight, grain L/B ratio, grain yield per plant and harvest index. The distribution pattern of the segregating generations revealed that, the F 3 's of the cross ADT 38 x ADT 37 for hundred seed weight and the F 3 's the cross ADT 38 x ADT 44 for grain yield per plant showed normal symmetrical distribution. The kurtosis value was almost negligible indicating mesocurtic nature of the distribution. The F 3 's of ADT 38 x ADT 44 recorded high mean coupled with higher coefficient of variation, indicating the presence of additive genetic control. The higher mean performance in F 3 may be due to accumulation of favourable genes. All the other crosses and generations showed asymmetric distribution in positive as well as negative direction, for almost all the characters of interest. The mean was comparatively higher but the coefficients of variation were comparatively lower, indicating the preponderance of non-additive genetic control in the expression of the traits of interest. It is better to resort to intermating of segregants followed by recurrent selection for further improvement. The F 3 's unique cross ADT 38 x ADT 44 had taken less number of days to first flowering, higher grain L/B ratio coupled with higher grain yield. A simple selection among the F 3 progenies of the cross ADT 38 x ADT 44 may yield some useful segregants with earliness, desirable grain quality and higher grain yield.

Regression analysis and inter generation trait association in F3 and F4 generation of wheat

“…Transgressive segregation may arise due to the dominance and dominance interaction and also by the additive x additive interaction which is fixable. Similar findings were reported by Thirugnanakumar et al (2011). Both the generation revealed the high mean and wide range of expression of different characters (Table 1 and Table 2) which indicates the presence of sufficient variability existed in the genetic material selected for the study and indicates the scope for selection of suitable breeding material for crop improvement Yadawad et al (2015), Shankarrao et al (2010), Kaushik et al (2013), Maurya et al (2014), Kalimullah et al (2012) and Basavaraj et al (2015) also reported similar results.…”