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. 2022 Mar 8;11(6):713.
doi: 10.3390/plants11060713.

Heritability and Associations among Grain Yield and Quality Traits in Quality Protein Maize (QPM) and Non-QPM Hybrids

Isaac Kodzo Amegbor  1   2 , Angeline van Biljon  1 , Nemera Shargie  3 , Amsal Tarekegne  4 , Maryke T Labuschagne  1
Affiliations

Heritability and Associations among Grain Yield and Quality Traits in Quality Protein Maize (QPM) and Non-QPM Hybrids

Isaac Kodzo Amegbor et al. Plants (Basel). .

Abstract

Maize (Zea mays L.) is the main staple cereal food crop cultivated in southern Africa. Interactions between grain yield and biochemical traits can be useful to plant breeders in making informed decisions on the traits to be considered in breeding programs for high grain yield and enhanced quality. The objectives of this study were to estimate the heritability of grain yield and its related traits, as well as quality traits, and determine the association between quality protein maize (QPM) with non-QPM crosses. Grain yield, and agronomic and quality trait data were obtained from 13 field trials in two countries, for two consecutive seasons. Significant genotypic and phenotypic correlations were recorded for grain yield with protein content (rG = 0.38; rP = 0.25), and tryptophan with oil content (rG = 0.58; rP = 0.25), and negative rG and rP correlations were found for protein with tryptophan content and grain yield with tryptophan content. Path analysis identified ear aspect, ears per plant, and starch as the major traits contributing to grain yield. It is recommended that ear aspect should be considered a key secondary trait in breeding for QPM hybrids. The negative association between grain yield and tryptophan, and between protein and tryptophan, will make it difficult to develop hybrids with high grain yield and high tryptophan content. Hence, it is recommended that gene pyramiding should be considered for these traits.

Keywords: correlations; heritability; path coefficient analysis; principal components.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Principal component analysis biplot of genotype-by-grain yield and other agronomic traits of 135 maize hybrids: GY, grain yield; EPP, ears per plant; PHT, plant height; EHT, ear height; EASP, ear aspect; HC, husk cover; SL, stalk lodging; RL, root lodging; ASI, anthesis-silking interval.
Figure 2
Figure 2
Principal component analysis biplot of genotype by quality traits of 135 QPM and non-QPM hybrids evaluated across six locations: Trypt_Pert, tryptophan; Prot, protein.
Figure 3
Figure 3
Combined principal component analysis biplot of 135 genotypes for grain yield, agronomic and quality traits: GY, grain yield; EPP, ears per plant; PH, plant height; EH, ear height; EASP, ear aspect; HC, husk cover; SL, stalk lodging; RL, root lodging; ASI, anthesis-silking interval; Trypt_Pert, tryptophan; Prot, protein.
Figure 4
Figure 4
Path analysis showing the relationship of grain yield and agronomic traits of maize hybrids: yield, grain yield; ER, ear rot; EPP, ear per plant, EA, ear aspect, HC, husk cover, ASI, anthesis-silking interval; EH, ear height; PH, plant height; DA, days-to-anthesis; RL, root lodging; SL, stalk lodging. Values in parentheses are correlation coefficients, and other values are direct path coefficients. R1 represents the residual effects.
Figure 5
Figure 5
Path analysis showing the relationship of grain yield, agronomic and quality traits of 135 QPM and non-QPM maize hybrids: yield, grain yield; ER, ear rot; EPP, ear per plant, EA, ear aspect, HC, husk cover, ASI, anthesis-silking interval; EH, ear height; PH, plant height; DA, days-to-anthesis; Trypt, tryptophan; Prot, protein. Values in parentheses are correlation coefficients, and other values are direct path coefficients. R1 represents the residual effects.
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