Genotype X environment interactions in sugarcane yield trials in the central-western region of Venezuela

La presencia de interacción genotipo x ambiente (G x A) es de suma importancia para los mejoradores, debido a que interacciones muy grandes pueden reducir la ganancia de la selección, complicando la identificación de cultivares superiores. Los objetivos de este trabajo fueron determinar la magnitud de la interacción G x A y evaluar la estabilidad fenotípica en caña de azucar (Saccharum spp. Hybrid) mediante el uso del coeficiente de regresión, la desviación de la regresión, la ecovalencia, el coeficiente de determinación y el coeficiente de variabilidad. Catorce genotipos y tres cultivares de caña de azúcar fueron evaluados en seis localidades durante dos años en Venezuela. La interacción G x A para rendimiento en caña y contenido de azúcar aparente (pol porcentaje caña) indica que los genotipos se comportan diferentes en cada localidad. La interacción de segundo orden no fue significativa para ambos caracteres. Los genotipos B80-549, B80-408 y B81-503 fueron significativamente superiores al resto de los materiales para rendimiento en caña, y B81-509, B84-25, B81-494 y B80-408 se destacaron en pol porcentaje caña. Este estudio sugiere que el análisis de estabilidad fenotípica puede contribuir con información suplementaria sobre el comportamiento de nuevas selecciones de caña de azúcar antes de la liberación como cultivares promisorios y puede incrementar la eficiencia en los programas de obtención de cultivares

Heritability and correlation among some selected morphological traits and their relationship with fall armyworm damage in sweet corn

ABSTRACT: Fall armyworm [Spodoptera frugiperda J. E. Smith] (FAW) is a serious pest in field corn and sweet corn [Zea mays L.] in many parts of the world. Sweet corn germplasm with effective levels of resistance to damage by the fall armyworm is needed to transfer resistance to commercial hybrids. The objectives of this study were to estimate heritability and to estimate the correlation among some selected morphological traits and their relationship with FAW damage. Seven shrunken-2 (sh2) inbred lines and four commercial sh2 hybrids of sweet corn were crossed to Mp708, a FAW-resistant field corn line. The F2 populations were subdivided with one half being selected for the sh2 trait and the other half was left unselected. Parent, F2, and F3 populations were artificially infested with FAW and evaluated for leaf damage caused by FAW. Heritability estimates for FAW resistance ranged from 0.22 to 0.61 depending on method of estimation used. The highest correlations occurred between silk color and anther color (0.70) and silk color and glume color (0.49). There were no consistent correlations of most morphological traits with FAWdamage. A linkage between white silk and shrunken-2 was observed.

Heritability and correlation among some selected morphological traits and their relationship with fall armyworm damage in sweet corn

Fall armyworm [Spodoptera frugiperda J. E. Smith] (FAW) is a serious pest in field corn and sweet corn [Zea mays L.] in many parts of the world. Sweet corn germplasm with effective levels of resistance to damage by the fall armyworm is needed to transfer resistance to commercial hybrids. The objectives of this study were to estimate heritability and to estimate the correlation among some selected morphological traits and their relationship with FAW damage. Seven shrunken-2 (sh2) inbred lines and four commercial sh2 hybrids of sweet corn were crossed to Mp708, a FAW-resistant field corn line. The F2 populations were subdivided with one half being selected for the sh2 trait and the other half was left unselected. Parent, F2, and F3 populations were artificially infested with FAW and evaluated for leaf damage caused by FAW. Heritability estimates for FAW resistance ranged from 0.22 to 0.61 depending on method of estimation used. The highest correlations occurred between silk color and anther color (0.70) and silk color and glume color (0.49). There were no consistent correlations of most morphological traits with FAW damage. A linkage between white silk and shrunken-2 was observed