Variation in yield and resistance to groundnut rosette disease in early- and medium-maturing groundnut genotypes in Nigeria

摘要

Groundnut rosette disease transmitted by aphids (Aphis craccivora Koch), is the most destructive disease of groundnut (Arachis hypogaea L) in sub-Saharan Africa. The objective of this research was to evaluate new breeding lines for resistance to groundnut rosette over several field locations and compare the disease ratings with pod yield. One hundred and thirty-four genotypes were evaluated for resistance to rosette and agronomic traits in three contrasting locations in Nigeria over three years. The genotypes were evaluated under both induced and natural rosette epidemics. Under induced disease epidemic, disease incidence raged from 0 on resistant to 100 percent on susceptible genotypes. Rosette incidence was variable under natural epidemics. Within locations, greater rosette incidence was significantly (P < 0.01) correlated with reduced pod yield. A high level of resistance to rosette was demonstrated in both early and medium-maturing genotypes. Genotypes resistant to rosette disease and superior to the widely grown cultivars in terms of acceptable pod yield, seed size and colour were identified.