Integrated management of groundnut rosette disease

Abstract

(Received 15 August, 2000; accepted 10 November, 2001) Abstract An investigation was conducted to study the effects of cultural practices and host-plant resistance on rosette disease incidence and pod yields of elite groundnut genotypes during four growing seasons in Malawi. The effects of genotypes and cultural practices, and their interactions on rosette disease incidence were significant at pegging stage under high disease pressure in all seasons. The genotypic differences in disease incidence were spectacular under high disease infestation in all seasons. Resistant genotypes gave higher pod yields than susceptible genotypes under high disease incidence, irrespective of sowing time and plant population. However, pod yields were higher for early sown treatments at optimum plant population. There were no marked differences in pod yield between genotypes under low disease pressure. Overall, the combination of resistant genotypes with early sowing at optimum plant population exhibited the best performance under high disease infestation. Although the resistant genotypes gave the highest pod yields under high disease infestation, pod yields were consistently lower than the yields under low disease situation probably because of their susceptibility to groundnut rosette assistor virus (GRAV) component. Key Words: Arachis hypogaea, cultural practices, genotypes, host-plant resistance, optimum plant population Resume Une enquete visant a evaluer les effets des pratiques agricoles et la resistance des plantes - hotes sur l'incidence de la rosette et le rendement en gousses des varietes - elites d'arachide, a ete realisee, durant 4 saisons culturales, au Malawi. Les effets de genotypes et de pratiques agricoles, et leurs interactions sur l'incidence de la rosette, ont ete significatifs, durant la periode de stabilisation, lorsque les plantes sont soumises sous une haute pression de la maladie. Les differences genotypiques sur l'incidence de la maladie, ont ete spectaculaire, durant toutes les saisons lorsque les plantes sont soumises sous une haute pression de la maladie. Les genotypes resistants ont donne des rendements en gousses plus eleves par rapport aux susceptibles, quelque soit la periode de semis et la densite des plantes. Cependant, les rendements etaient eleves pour un semis precoce realisee a la densite des plantation optimale. Au point de vue de rendement en gousses, des differences non significatives, entre les genotypes, etaient obsrvees lorsque les plantes etaient soumises sous faible pression de la maladie. Les meilleures performances de rendement, lorsque les plantes sont soumises sous hautes pressions, ont ete observees, lorsque l'on combine genotypes resistants et semis precoces. Malgre que les genotypes resistants ait donne, un rendement eleve en infection elevee, les rendements etaient moins eleves par comparaison a la situation de faible pression, probablement a cause de leur sensibilite aux composantes du GRAV. Mots Cles: Arachis hypogaea, resistante des plantes- hotes, pratiques agricoles (Af Crop Sci J 2002 Vol 10 No 1 pp99-110)