Genetic Analysis of Grain Yield and Other Traits for NewYellow Maize Inbred Lines under Different Locations

INTRODUCTION

Maize is one of the most important strategic crops in Egypt, which seeks to achieve self-sufficiency in it. Therefore, producing high-yielding hybrids that are compatible with environmental conditions is one of the most important goals of the maize research department. Production  high yielding hybrids of maize   depend on the behavior of the line itself and the behavior of line in cross. Combining ability analysis is one of the powerful tools available to estimate the combining ability effects and selecting the desirable parents and crosses for the exploitation of heterosis. It is also  important to have information on the nature of combining ability of parents, their behavior and performance in hybrid combination (Chawla and Gupta 1984).The behavior of  the line is assessed through the estimation of general combining ability (GCA) and specific combining ability (SCA) effects. GCA enabled breeders to exploit the existing variability in the breeding materials, to identify individual genotypes conferring desirable attributes and to distinguish relatedness among genotypes (Vacaroet al., 2002). While SCA is serving to determine heterotic patterns among populations or inbred lines, to identify promising single crosses and to assign inbred lines into heterotic groups (Vasal et al., 1992; Hede et al., 1999 and Revilla et al., 2002). Line × tester analysis provides information on GCA of parents and SCA of  hybrids  which  helps  to  identify  good  inbred  lines  and  hybrids respectively  (Silva  et  al., 2010  and  Moterle et al., 2011). The non- additive gene effects was controlling in the inheritance, for grain yield trait (Ngoune et al.,  2015, Akula et al., 2016, Mbuvi et al  2018 and Mosa et al., 2024b). while, the effect was greater in the inheritance of grain yield. Badu-Apraku et al., (2015)  and  Mosa et  al  (2024a)

The main aims of this study are (a) to estimate of  general and specific combining ability of 13  inbred line for grain yield and other traits. (b) identify the type of gen action  effected  in the inheritance of traits (c) identify the superior hybrids to improve the yielding ability.

MATERIALS AND METHODS

Thirteen new yellow maize inbred lines derived from different resources Table (1) were crossed with three yellow maize inbred lines developed as testers, i.e. Gm-1021, Gm- 6052 and Gz-658 in 2023 growing season at Gemmeiza research station. In 2024 growing season, the resulting 39 crosses along with check single cross (SC 168) were evaluated in three locations i.e. Gemmeiza, Sakha, and Sids Res. Sta. A randomized complete blocks design (RCBD) with three replications was used in evaluation. Plot size was one row, 6 m. long, 0.80 m. wide and 0.25. m between hills. Cultural practices were done as recommended. Data were recorded on different traits, i.e. days to 50% silking, plant height (cm), ear height (cm), and grain yield in ardab/feddan (ard/fed.) (One ardab= 140 kg, feddan = 4200 m²) adjusted to 15.5% grain moisture. A combined analysis of variance across three locations was performed when the homogeneity test was calculated according to Bartlett, M.S. (1937) and Snedecor and Cochran (1989). Combining ability effects were computed according to line × tester analysis for all studied traits when the mean squares due to crosses were significant based on the method described by Kempthorne (1957). Calculation of analysis of variances and line x tester analysis were carried out by using  SAS (1999).

Table(1). Name and origin of the thirteen yellow maize inbred lines.

RESULTS AND DISCUSSION

The combined analysis of variance for all studied traits across three locations is presented in Table 2. Mean squares due to locations(Loc.) were highly significant for all studied traits under this study, meaning that the conditions were differed from location to another. These results are in agreement with those of  Ismail et al (2024). Genotypes mean squares were highly significant for all studied traits, indicating that there were differences among the genotypes. These results are in agreement with those of Abu Shoshaet al., (2020) and Abd El-Latif et al (2024). The interaction between genotypes with locations was highly significant for all studied traits,  meaning that the crosses were affected by change of locations.

Table (2). Combined analysis of variance for all studied traits of 40 genotypes across three locations.

*, ** Indicate to significant and highly significant differences at 0.05 and 0.01 levels of probability, respectively.

Mean performance of the 39 crosses and one check for days to 50% silking, plant height, ear height, and grain yield are presented in Table (3). For days to 50 % silking, sixteen single crosses were significantly earlier than the check SC 168.  (63 days). The earliest crosses among them were (L-1 x Gm. 1021), (L-1 x Gm. 6052), (L-3 x Gm1021), (L-6 x Gm. 1021) and (L-6 x Gm. 6052)  (60 days).

Table (3). Mean performance of 39 new yellow maize crosses for all studied traits across three locations.

For plant height, crosses ranged from (244.67 cm) for (L-5 x Gz-658) to (294.89 cm) for (L-13 x Gm- 1021) and one cross (L-5 x Gz.658) (244.67 cm) was found to be significant for short plant height compared to the check SC 168 (263.67 cm).For ear height, two crosses (L-5 x Gz-658) (136.11 cm) and (L5 x Gm1021) (143.78 cm) were significant for low ear height than check (154.44 cm).

For grain yield, six crosses (L-2 x Gz 658) (26.11 ard/fed), (L-3 x Gm.1021) (27.39 ard/fed), (L-3 x Gm.6052) (26.12 ard/fed), (L-4 x Gm.6052) (28.67 ard/fed), (L-11 x Gm.6052) (26.10 ard/fed) and (L-13 x Gm.658) (26.42 ard/fed) significantly out-yielded  the check hybrid SC 168 (23.69 ard/fed). Hence, these hybrids will be advanced for further evaluation.

Table (4). Line x tester analysis of variance for all studied traits of 39 crosses across three locations.

*, ** Indicate to significant and highly significant differences at 0.05 and 0.01 levels of probability, respectively.

Line × tester analysis for days to 50% silking, plant height, ear height, and grain yield under combined analysis across the three locations is presented in Table 4. Significant and highly significant mean squares due to crosses and their partitions (lines, testers and lines x testers) obtained for all studied traits, except testers for grain yield,  revealed  that a wide variability among crosses and parental lines and testers for these traits. similar  results were obtained by Aboyousefet al., (2016), Abdel-Moneamet al., (2020). Alsebaey et al., (2021).  Mean squares due to interactions between lines (L.), testers (T.) and lines x testers (L × T) with locations (Loc.) were significant and highly significant for all studied traits, except (L. x T. x Loc.) for ear height, indicating that the lines and testers performed differently under the three locations for these traits.  Similar results were reported, Gamea (2015) and Abu Shosha and Habouh (2019).

Table (5). Proportional contributions of lines, testers and their interaction to total variation.

The proportional contributions of lines, testers and their interaction to the total variation of crosses are presented in Table (5). for ear height and grain yield, the proportional contributions to the total variation of crosses were due to inbred lines, while, for days to 50 % silking and plant height it were due to testers and line x tester, respectively. Similar results were reported by Alsebaey et al (2021)

Table(6). Estimates of genetic parameters for all studied traits across three locations.

The results in Table 6 showed that specific combining ability (SCA) effects (K²SCA) was higher than general combining ability (GCA) effects (K²GCA) for  plant height and grain yield traits,  indicating that non-additive gene effects were more important than additive gene effects in the inheritance of this traits, while the reverse was obtained for days to 50% silking and ear height traits the additive gene effect was greater than the non- additive effects. These results are similar to those reported by Italia et al., (2022)  and Adewale et al., (2023). The K² SCA x L was higher than that due to K² GCA x L for  plant height and grain yield traits, indicating that the non- additive gene effects more interacted more with locations than additive gene effects for these traits, while, the reverse was obtained for days to 50% silking and ear height traits. Similar results are reported by Akula et al.,(2016)Ismail et al., (2023) and Tabu et al., (2023)

Table (7). Estimates of general combining ability (GCA) effects for 13 inbred lines and three testers across three locations.

*, ** significance and highly significant differences at 0.05 and 0.01 levels of probability, respectively.

The general combining ability effects (ĝi) of thirteen inbred lines plus three testers for studied attributes are displayed in Table (7). Highly significance and negative value of GCA effects for earliness were detected by the inbred lines (L-1, L-2 and L-6). These inbred lines could be used to good benefit in maize programs for breeding early maturing hybrids. The inbred lines (L-1 and L-5) were identified as good combiners for short plant and ear height meaning that there inbred lines can be used to maize breeding  programs to obtain good hybrids for short plant and ear height. The five inbred lines (L-2, L-3, L-4, L-11 and L-13) could play crucial role for producing new high yielding hybrids of maize because they had significant favorable GCA effects for grain yield. The results showed that, the tester Gm-1021possessed the desirable significant GCA effects for earliness  characters. While the tester Gz-658 showed desirable GCA effects for plant height and ear height. Many researchers confirmed on the importance of the GCA effects selection in the maize breeding program (Hundera  (2017), Motawei et al., (2019), Abd-El aziz et al., (2021) and Mosa et al., (2024b)

Table(8). Estimates of specific combining ability (SCA) effects of 39 crosses all studied traits across three locations.

Specific combining ability (SCA) effects of the 39 crosses for examined characters are presented in Table (8).

For days to 50% silking, three crosses (L-5 × Gz 658 , L-9 × Gm 6052 and  L-10 × Gm 1021) had significant and negative values of SCA effects for earliness. For plant height, the five crosses( L-5 × Gz658) , (L-8 × Gm 1021), (L-10 × Gm 6052), (L-11 × Gm 1021) and (L-12 × Gz 6052) had significant and negative SCA effect. Similarly, the significant favorable SCA effects were obtained by the two crosses (L-8 × Gm 1021) and (L-10 × Gm 6052) for ear height. Five crosses viz. (L-1 × Gz658) , (L-4 × Gm 6052), (L-6 × Gm 6052),  (L-7 × Gm 6052) and  (L-10 × Gm 1021) had significant and positive values of SCA effects for grain yield. The (SCA) effects could assist breeders to detect heterotic pattern among genotypes in order to pick up promising single crosses for targeting traits Abdel-Moneam et al., (2020) andMosa et al., (2016).

Table(9). Superiority percentage  of 39 new yellow maize crosses to one check across  for all studied traits across three locations.

Superiority percentages related to the one check, i.e. SC.168 , for the 39 F1s crosses, under combined data are presented in Table (9).  For earliness,  sixteen  crosses out of 39 crosses showed superiority % over the check hybrid (SC.168) for this trait. The best crosses for earliness over the check were (L-1 x Gm. 1021), (L-1 x Gm. 6052), (L-3 x 1021), (L-6 x Gm. 1021) and (L-6 x Gm. 6052). One cross (L-5 x Gz-658) and two crosses (L-5 x Gz-658) and (L5 x Gm1021) had Superiority percentages for short plant height and low ear position respectively. For grain yield, six maize hybrids (L-2 x Gz 658), (L-3 x Gm.1021), (L-3 x Gm.6052), (L-4 x Gm.6052), (L-11 x Gm.6052) and (L-13 x Gm.658) had significant superiority percentages significant ranged from 10.17* to 21.02** ,while, the best hybrids were (L-3 x Gm. 1021) and (L-4 × Gm.6052) which gave the highest gave percentages (15.60** and 21.02**) respectively,  relative to the check hybrid SC.168. Several investigators reported useful superiority for yield in maize (Patel et. al., 2019; Aboyousef et al., 2022 and  Karim et al., 2022).

CONCLUSION

This study has identified the tester Gm-1021as a good combiner for earliness. While the tester Gz-658 displayed favorable GCA effects for plant and ear heights. The parental lines L-1, L-2 and L-6 might be exploited as good combiners for earliness. Similarly, the inbred lines (L-2, L-3, L-4, L-10 and L-13)  for improving grain yield trait. Remarkably, six crosses; (L-2 x Gz 658), (L-3 x Gm.1021), (L-3 x Gm.6052), (L-4 x Gm.6052), (L-11 x Gm.6052) and (L-13 x Gm.658)  significantly out-yield the check hybrid (Sc 168) and could be considered as promising hybrids. Consequently, these hybrids could be exploited for commercial release after evaluating yield stability across changing environments.