Evaluación de la Antibiosis, Antixenosis, y Tolerancia de Melanaphis sacchari/sorghi1 en Híbridos de Sorgo2.

En México no existe un programa de fitomejoramiento específico que use progenitores con fuentes marcadas con genes dominantes que confieran resistencia o tolerancia del sorgo a Melanaphis sacchari/sorghi. Resultados preliminares indicaron que M. sacchari tiene una menor preferencia (antixesosis) por los híbridos Ámbar, P15, y Milenia. La menor tasa intrínseca de incremento poblacional (rm) se obtuvo en los genotipos Ámbar y 85 P 20, y se comprobó la tolerancia en Ámbar, Cobalto, y 85 P 20, manifestada con las variables, área foliar, peso seco y el índice clorofílico. Estos resultados, deben ser considerados como un avance importante en las futuras estrategias de manejo y programas de mejoramiento vegetal que se ejecuten para el combate de M. sacchari/sorghi en sorgo. To date, there is limited information on sources of resistance to Melanaphis sacchari/sorghi , in Sorghum bicolor (L.) Moench hybrids. These cultivars are sold by different seed companies in Mexico, basing their recommendations fundamentally on the potential yield of each genotype. So, there are no specific breeding programs that use sources marked from progenitors with dominant genes that confer resistance or tolerance to the insect. The objective of this study was to evaluate resistance mechanisms such as antixenosis, antibiosis, and tolerance in six commercial sorghum hybrids against M. sacchari at Morelos. Preliminary results indicated the aphid had less preference (antixenosis) for Ambar, P15, and Milenia hybrids. The antibiosis shown through the Lower Intrinsic Rate of Population Increment (rm), occurred in genotypes Ambar and 85 P 20, and there is evidence of tolerance based on the variables leaf area (AF), dry weight (PS), and chlorophyll index (Cl), with Ambar, Cobalt, and 85 P 20. These results should be considered an important advance in future management strategies and programs for the control of M. sacchari/sorghi in sorghum. [ABSTRACT FROM AUTHOR]