Combining ability analysis of quality protein maize (QPM) inbred lines for grain yield, agronomic traits and reaction to grey leaf spot in mid-altitude areas of Ethiopia

Abstract

A study was carried out to study the combining ability effects of diallel cross hybrids for grain yield, agronomic traits and reaction to grey leaf spot (GLS). Forty five experimental diallel cross hybrids made from ten quality protein maize (QPM) inbred lines with varying level of resistance to GLS were evaluated along with three checks at Bako and Jima Research Centers during 2014/2015 cropping season. Analysis of variance showed significant variation (P≤0.05) among genotypes and between environments. This depicted the existence of genetic variation among genotypes in all studied traits. Mean squares characterized by general and specific combining ability effects were significant for the most traits and this suggested that both additive and non-additive gene actions have the contribution in the expression of the traits. However, the ratio of General combining ability (GCA) to specific combining ability (SCA) sum of squares were greater than unity, this revealed that there was preponderance of additive gene action in the expression of all the traits under study. Among inbred lines studied P6 and P10 had a desirable GCA effects for grain yield whereas P1, P4 and P10 were the best general combiners for GLS resistance. Furthermore, P10 was identified as good general combiner for grain yield as well as GLS is therefore recommended to be used in breeding programs with a purpose of developing both high yielder as well as GLS disease resistant genotypes. Crosses, P2×P8 and P4×P6 showed the most desirable performances and SCA effects for grain yield. Grain yield showed positive correlation between ear per plant, plant and ear height, and ear position whereas negative correlation were observed with GLS, days to anthesis, days to silking, plant aspect and ear aspect traits. The information which is generated in this study could be helpful to develop high yielding maize varieties with good agronomic traits as well as GLS resistance.

Heterotic groupings, perse performance and standard heterosis of quality protein maize (Zea mays L.) for yield and yield contributor traits adapted at mid altitude of Ethiopia

“…In agreement with this finding, significant mean square due to genotypes for grain yield and yield related traits in maize were also reported by previous investigators [31,15,53,10,21,4] .…”

Combining Ability Study for Grain Yield and Agronomic Traits of Quality Protein Maize (Zea mays L.) Inbred Lines Adapted to Mid-Altitude Agroecology of Ethiopia

“…The negative significant GCA effect has a tendency to reduce plant height whereas the positive significant has a trend to increase plant height in the crosses of offspring. These findings had resembled results with the preceding study of various authors (Matin et al, 2016;Bitew et al, 2017 andMelkamu et al,2020). In the same way, T1 (positive), T3 and T4 indicated positive and negative significant GCA effects for plant height whereas T1 and T3 showed significant GCA effects for EH to across locations (Table -3).…”

“…In line with this study, many maize researchers also have reported significant differences in GCA for grain yield and yield-related traits in different maize genotypes studied. Legesse et al (2017), Tolera et al (2017), Bitew et al (2017) and Gemechu et al (2020) in separate study suggested that both GCA and SCA effects are significant and important for grain yield and most other traits studied.…”

“…For instance; Keimeso et al (2020) combining ability of highland adapted maize DH lines for desirable agronomic traits and reported that positive and negative significant GCA effects for the traits of grain yield, days to silking, days to anthesis, plant height, ear per plant height, ear diameter and thousand kernel weights. Bitew et al (2017) studied combining ability analysis of quality protein maize inbred lines for grain yield, agronomic traits, and reaction to grey leaf spot in midaltitude and reported that positive and negative significant GCA effect for the traits grain yield, days to anthesis, days to silking, anthesis silking interval, plant and ear height, gray leaf spot and ear per plants.…”

Genetic Analysis and Hybrid Performance for Yield and Yield Related Traits in Diallel Crosses of Mid-Altitude Maize (Zea mays L.) Inbred Lines

“…The current results are in line with the findings [37]; [38]; [39]; [25]; [40]; [13]; [26] and [41].The higher grain yield records were obtained from the crosses of L1 x L4 (11.79 ton ha -1 ), L2 x L4 (10.67 ton ha -1 ), L1 x L5 (10.42 ton ha -1 ), L7 x L8 (10.20 ton ha -1 ) L4 x L6 (10.1 ton ha -1 ) as compared to best performing check BH546 (9.93 ton ha -1 ) (Table 3) indicating that the two combined inbred lines in each crosses might be genetically diverse or belong to different heterotic groups. [42]and [43] reported that the performance of maize hybrids for grain yield greatly depends on the level of heterosis expressed in their hybrids and can be maximized by crossing inbred lines belonging to different heterotic groups. Contrarily, the lowest grain yield was recorded from the crosses of L8 x L10 (5.84 ton ha -1 ) indicating that the two inbred lines are genetically similar or belonging to same heterotic groups.…”