Agronomic and qualitative performance of some experimental Burley hybrids in Malawi
Malawi mainly depends on tobacco for forex generation, with Burley as a major contributor. However, the country has a limited choice of high yielding and disease resistant varieties against a plethora of disease constraints, particularly root-knot nematodes, fusarium wilt and angular leaf spot. Six improved experimental hybrids and four checks were simultaneously screened in randomised complete blocks (RCBD) with three replications in disease hotspots, and evaluated for yield and quality in rotated lands at four sites in central Malawi in the 2017-2018 and 2018-2019 seasons. Screening focussed on reaction of genotypes to root-knot nematodes (assessed on a 0-10 scale) and proportion of plants infected by fusarium wilt diseases. BRK4 and ABH12 were used as nematode resistant checks while ABH31 and ABH43 served as nematodes and fusarium wilt resistant checks. Two-row plots were used in each case with an inter-row spacing of 1.2 m. Each row had 12 plants spaced at 0.6 m apart. Yield evaluation followed recommended production practices for Burley while no topping and desuckering were done in screening plots. Data was collected on disease ratings for root-knot nematodes and fusarium wilt and other traits of agronomic relevance. Results revealed significant differences with regard to reaction of test hybrids and checks to root-knot nematodes at 6 WAT and 9 WAT (P < 0.05). Except HIP-15-20, all other hybrids were as resistant as the nematode resistant check, BRK4. All test hybrids except HIP-15-18, recorded significantly (P < 0.05) lower mean fusarium wilt infected plants compared to the checks. Yield, colour spectrum and grade outturn of cured leaf did not show significant differences between the hybrids and checks implying that agronomic performance was similar.