Genetic Diversity and Combining Ability of White Maize Inbred Lines under Different Plant Densities

Abstract

Knowledge of combining ability and genetic diversity are important prerequisites for the development of outstanding hybrids that are tolerant to high plant density. This work was carried out to assess general combining ability (GCA) and specific combining ability (SCA), identify promising hybrids, estimate genetic diversity among the inbred lines and correlate genetic distance to hybrid performance and SCA across different plant densities. A total of 28 F1 hybrids obtained by crossing eight adverse inbred lines (four local and four exotic) were evaluated under three plant densities 59,500 (D1), 71,400 (D2) and 83,300 (D3) plants ha−1 using spilt plot design with three replications at two locations during 2018 season. Increasing plant density from D1 to D3 significantly decreased leaf angle (LANG), chlorophyll content (CHLC), all ear characteristics and grain yield per plant (GYPP). Contrarily, days to silking (DTS), anthesis–silking interval (ASI), plant height (PLHT), ear height (EHT), and grain yield per hectare (GYPH) were significantly increased. Both additive and non-additive gene actions were involved in the inheritance of all the evaluated traits, but additive gene action was predominant for most traits. Inbred lines L1, L2, and L5 were the best general combiners for increasing grain yield and other desirable traits across research environments. Two hybrids L2 × L5 and L2 × L8 were found to be good specific combiners for ASI, LANG, GYPP and GYPH. Furthermore, these hybrids are ideal for further testing and promotion for commercialization under high plant density. Genetic distance (GD) among pairs of inbred lines ranged from 0.31 to 0.78, with an average of 0.61. Clustering based on molecular GD has effectively grouped the inbred lines according to their origin. No significant correlation was found between GD and both hybrid performance and SCA for grain yield and other traits and proved to be of no predictive value. Nevertheless, SCA could be used to predict the hybrid performance across all plant densities. Overall, this work presents useful information regarding the inheritance of maize grain yield and other important traits under high plant density.

Incorporated Biochar-Based Soil Amendment and Exogenous Glycine Betaine Foliar Application Ameliorate Rice (Oryza sativa L.) Tolerance and Resilience to Osmotic Stress

“…In the present investigation, the decrement in the number of panicles/m 2 , 1000 grain weight (g), and the number of grains/panicles which negatively affecting grain yield, straw yield, and harvest index under water stress and soil salinity was ascribed to the inhibition in the absorption and transfer of the nutrition materials through the growth of grains and their filling periods. Furthermore, soil salinity can trigger harsh injury to the ovary, and thus may lead to a decrease in the yield [ 57 ]. In terms of yield and its components, significant differences were observed between different wheat genotypes growing under different water regimes in the Cerrado region in Brazil [ 58 ].…”

Utilization Efficiency of Growth Regulators in Wheat under Drought Stress and Sandy Soil Conditions

“…The number of days to 50% heading was recorded after 50% of spikes were emerged in each treatment including the replicates. Flag leaf area (cm 2 ) was determined according to the following formula by Dodig et al [30]:…”

Comportamiento genético para componentes de rendimiento en una población de maíz enano

“…Los resultados indican, que la ACG contribuyó con 66% a la suma de cuadrados en la variable de longitud de mazorca, 21% para profundidad de grano, 23% para peso hectolítrico y 65% para rendimiento, dándonos una idea clara de que longitud de mazorca y rendimiento tendrán una mayor heredabilidad comparada entre las variables estudiadas, tal como se comprueba en el (Cuadro 6). Estos resultados concuerdan con los encontrados por Al-Naggar y Atta (2014); Kamara et al (2020). El efecto de ACE obtuvo mayor contribución en la expresión del peso hectolítrico aportando 47%, esto implica que este carácter está controlado principalmente por efectos no aditivos o de dominancia.…”

“…Estas diferencias encontradas en ACG, se pueden atribuir a la base genética de donde se derivaron los progenitores, los cuales ha pasado por varios ciclos de selección recurrente.Al no detectar significancia en el peso hectolítrico y profundidad de grano se sugiere que es necesario propiciar la variabilidad para estos caracteres y así, lograr incrementar la varianza Luna et al (2013)Haochuan et al (2014), mencionan que tener conocimiento amplio de la base genética del germoplasma y del tipo de acción génica de los caracteres de mayor importancia económica, como el rendimiento, esto permite maximizar la varianza genética y de esta forma incrementar y fijar la frecuencia de alelos favorables en la población.En cuanto ACE, se detectó significancia para peso hectolítrico (p≤ 0.05), lo que indica que existe efecto de dominancia; es decir, la variabilidad genética no aditiva para este carácter fue importante Kamara et al (2020),. indican que los efectos significativos de ACG y ACE implica que tanto los efectos aditivos como los no aditivos están involucrados en el gobierno de los caracteres.El aspecto práctico del mejoramiento genético del maíz por hibridación está basado en el desarrollo de líneas endogámicas y la evaluación de su ACG y ACE para la obtención de híbridos comerciales de alto de rendimiento.…”