Diversity And Genotype X Environment Interaction Of Bean Landraces In Bukoba And Missenyi Districts Of Tanzania

ABSTRACT

A field experiment was conducted during the 2008/09 short rain season in three major

agro-ecological zones of Bukoba and Missenyi districts, Tanzania. The agroecological

zones were characterized as follows based on the amount of rainfall: high (≥1500 mm),

medium (1200 mm) and low (800 mm). Objectives of the study were to investigate the

diversity of bean landraces in the areas, assess the effect of environment on genotypes

performance, determine relationship among plant characteristics and their contribution to

seed yield. Thirty eight bean landraces were collected from farmers in the two districts and

evaluated in three locations: ARI- Maruku, Kyema and Byamutemba in high, medium and

low rainfall zone, respectively. A Randomised Complete Block Design was used with three

replications. Data collected were: days to 50% flowering, days to 90% maturity, plant

height, number of pods per plant, number of seed per pods, 100 seed weight, grain yield

and disease reaction. Data analysis revealed significant variations among genotypes for all

characters investigated and significant genotypes x environment interactions for yield and

yield components. Environmental factors reduced seed yield by 76% and by 39% in low

and high rainfall zones, respectively, compared to the medium rainfall zone. Kamoshi gave

significantly higher seed yield across locations. Seed yield had positive highly significant

correlations with pods per plant and seeds per pod. Path coefficient analysis showed that,

seeds per pod contributed most to seed yield. Stability parameters estimates indicated that

genotypes had significantly different seed yield performance across environments,

suggesting for multi-location testing for seed yield. However, Kamoshi had seed yield

stability across the environments. The study findings suggest existence of diversity among

the bean landraces and that their responses differ with environments. Future studies should

focus on genotyping of the landraces to determine the extent of their diversity and

performance in diverse production environments