Morpho – physiological characteristics determining yield in semi determinate tomato (Lycopersicum esculentum) germplasm

Abstract

Increasing yield through selection for yield per se is slow and sometimes difficult to achieve since yield is a quantitatively inherited trait with low heritability. Yield can be indirectly increased by selecting for yield components that are highly correlated with yield but possess higher heritability. Semi-determinate tomato comprised five genotypes and a check variety were evaluated at Sebele Horticultural Research Station during 2010/11 growing season to determine yield and yield components, and the correlation among the components that explain most of the variation in tomato yield. It was also done to determine the direct and indirect effects of the morpho-physiological traits on the yield in tomato. The experiment was laid out in randomized complete block design with four replications. Data collected was yield, marketable fruit number, plant height, fruit number per truss, number of trusses per plant, the weight of fruits per truss, fruit number per plant, the weight of fruits per plant, single fruit weight, flower numbers per truss, days to 50 percent flowering, fruit dry matter and total soluble solids. Four statistical tools used to analyse the collected data was ANOVA, correlation, stepwise multiple regression and path coefficient analysis. The analysis of variance for yield and its components revealed a significant difference (p<0.05) between the cultivars in the following components; yield, marketable fruit number, fruit weight per truss, Days to 50% flowering and plant height. Stepwise multiple regressions revealed that the identified components which explain variation in yield accounted for 81.84% as per the result of the coefficient of multiple determinations (R2). The path coefficient analysis identified marketable fruit number (0.989) and fruit weight per truss (0.592) as the most important components of tomato fruit yield. This is in as much as the correlation of marketable fruit number (r = 0.68) was significant at p<0.05. However, the correlation of the second component fruit weight per truss (r= 0.352) was not significant at p<0.05. Marketable fruit numbers have a strong positive direct influence on yield. Two other important components to consider for yield improvement in tomato are fruit weight per truss and single fruit weight.