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The nature and magnitude of genetic effects on morpho-yield traits were studied in a 6 × 6 F 1 and F 2 diallel cross in upland cotton. An additive-dominance model was adequate for most of the traits except plant height and seed cotton yield, where the model was partially adequate. Genetic parameters were estimated following Hayman's and Mather's model. Additive effects controlled lint percentage and monopodia in both generations, and plant height and sympodia in F 2 . Non-additive inheritance with over-dominance controlled yield in both generations, and plant height and sympodia in F 1 . Most traits presented an unequal proportion of positive (U) and negative (V) alleles in the loci (H 2 < H 1 ) and an asymmetrical distribution of genes in the parents (H 2 /4H 1 < 0.25 and F different to zero). The value of H 2 /4H 1 was lower than maximum value (0.25) for all of traits, which arises when U = V = 0.5 over all loci. The proportion ͌ʳʲ 4DH1 ʲʲ + F ʲ/͌ʳʲ 4DH1 ʲʲ -F ʲ) confirmed by half of the traits that dominant alleles were in excess as compared to recessive alleles. Dominance effects (h 2 ) for most of the traits suggested that substantial contribution of dominance was not due to heterogeneity of loci in these parameters. Broad and narrow sense heritabilities were high for most of the traits. Correlation coefficient between the Wr + Vr and mid parental (y) indicated that dominant genes were responsible for increased sympodia, lint % and yield, and recessive genes increased monopodia and plant height. Genetic gain was encouraging for most traits. Cultivar CIM-1100 was identified by genetic advancement as a promising parental cultivar to cross combinations.Additional key words: additive-dominance model; additive and dominance effects; D, H 1 & H 2 genetic components of variance; seed cotton yield; upland cotton. ResumenEfectos genéticos en caracteres morfológicos y de rendimiento en algodón (Gossypium hirsutum L.)Se estudió la naturaleza y la magnitud de los efectos genéticos sobre los caracteres morfo-productivos en un cruce dialélico F 1 y F 2 de 6 × 6 en algodón tipo upland. Para la mayoría de los caracteres, excepto altura de planta y rendimiento de semilla, fue adecuado un modelo aditivo-dominante. Se estimaron los parámetros genéticos según Hayman y Mather. Los efectos aditivos controlaron el porcentaje de pelusa y los monopodios en ambas generaciones, y la altura de la planta y los simpodios en la F 2 . La herencia no aditiva con superdominancia controló el rendimiento en ambas generaciones y la altura de planta y los simpodios en la F 1 . La mayoría de los caracteres presentaron una proporción desigual de alelos positivos (U) y negativos (V) en los loci (H 2 < H 1 ) y una distribución asimétrica de los genes en los parentales (H 2 /4H 1 < 0,25 y F 0). El valor de H 2 /4H 1 estuvo por debajo del valor máximo (0,25) para todos los caracteres, lo que surge cuando U = V = 0,5 en todos los loci. La proporción ͌ʳʲ 4DH1 ʲʲ + F ʲ/͌ʳʲ 4DH1 ʲʲ -F ʲ) confirmó, para la mitad de los caracteres, que había un exc...

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Overall, maize genotypes showed early maturity in plain areas (CCRI and Haripur) but higher yield in hilly areas (Mansehra and Swat). © 2017 Society of Chemical Industry.