Combining ability and heterosis studyin maize inbreds throughout diallel mating design

Abstract

Combining ability effects were estimated for grain yield and some other important agronomic traits of maize in a 7×7 diallel analysis excluding reciprocals. The variances for general combining ability (GCA) were found significant for yield, days to pollen shedding, days to silking and ear height while it was found non-significant for plant height and number of kernels/ear. Non-significant general combining ability (GCA) variance for plant height and number of kernels/ear indicates that these two traits were predominantly controlled by non- additive type of gene action. Specific combining ability (SCA) was significant for all the characters except yield and days to silking. Non-significant specific combining ability (SCA) variance for yield and days to silking suggests that these two traits were predominantly controlled by additive type of gene action. Both GCA and SCA variances were found significant only in days to pollen shedding and ear height indicated the presence of additive as well as non additive gene effects for controlling the traits. However, relative magnitude of these variances indicated that additive gene effects were more prominent for all the characters studied except days to silking. Parent BIL95 was the best general combiner for both high yield and number of kernels/ear and parent BML4 for dwarf plant type. Two crosses (BML4× BML36 and BIL114× BIL31) exhibited significant and positive SCA effects for grain yield involved low × average and average × average general combining parents. The range of heterosis expressed by different crosses for grain yield and days to silking was from -65.83 to 21.26 percent and -17.85 to 8.22 percent, respectively.. The better performing three crosses (BIL114×BIL31, BIL138×BIL95 and BIL31×BIL95) can be utilized for developing high yielding hybrid varieties as well as for exploiting hybrid vigour.Bangladesh J. Agril. Res. 43(4): 599-609, December 2018

Gene actions and combining ability effects on grain yield and its constituent traits in inbred lines of quality protein maize

“…This finding pointed out that dominant or non-additive types of gene activity predominate in these genotypes. This result is in contrast with Tilahun et al (2017) and Karim et al (2018) who reported prevalence of additive gene action for all the traits except days to silking. Dominant or nonadditive gene action was also reported by Yerva et al (2016), Kumar et al (2017), Hassan et al (2019) and Arunkumar et al (2022).…”

“…The parents involved in theses crosses also showed good general combining ability effects and performed substantially better in specific crosses. E1-Shamarka et al (2015), Basser et al (2021) and Arunkumar et al (2022) also reported desirable significant negative sca effects for earliness in their experiment while Karim et al (2018) reported non-significant sca effect for days to 50% silking Most of these crosses have at least one parent with low gca effects. Significant negative sca effects for PH were observed in five crosses, namely Q5 x Q7 (-39.47), Q5 x Q8 (-23.20), Q6 x Q7(-13.57) Q1 x Q3 (-12.94) and Q3 x Q4 (-10.54), and for EH four crosses, namely Q6 x Q7(-29.50), Q5 x Q7(-26..43), Q5 x Q8 (-18.77) and Q2 x Q4 (-8.87) showed significant negative sca effects.…”

“…When it comes to PH and EH, significant negative gca effects were Environment Conservation Journal 2020) also reported significant negative gca effects for plant and ear height. Karim et al (2018) found nonsignificant gca effect for plant height. The parents (Q6, Q7, and Q8) showed good combining ability for lowered plant and ear height characters and can be utilized for development of short stem-type plants.…”

Combining Ability and Heterosis of QPM Hybrids for Yield, Qualitative and Quantitative Traits under Heat stress in Different Environments

“…Similarly, over check, HQPM-5 a total of 12 hybrids recorded significant standard heterosis in desirable positive direction in leaf area index. These results were in line with the findings of Mohammed and Yousif (2020) and Karim, A.N.M.S et al [28]. The highest grain yield was recorded in the hybrid P 5 X P 7 (188.41 q/ha) and this hybrid differed significantly over the best check for seed index, cob length, plant height and starch content.…”

Combining ability and testcross performance of multi-nutrient maize under stress and non-stress environments

“…To develop highly productive multi-nutrient maize hybrids, breeders should know the GCA and SCA of inbred lines, since they both indicate the breeding value of inbred lines in hybrid combinations ( Karim et al., 2018 ). GCA has been defined by Sprague and Tatum (1942) as the average performance of the inbred line based on its performance in crosses with other inbred lines.…”