EVALUATION OF SOME TOMATO YELLOW LEAF CURL VIRUS-RESISTANT COMMERCIAL TOMATO HYBRIDS AND THEIR F2 POPULATIONS

Abstract

The economic feasibility of using the tomato yellow leaf curl virus (TYLCV)- resistant F1 tomato hybrids may be improved with the possibility of using their F2 generation in commercial production. Hence, this study was conducted to evaluate the F1 and F2 generations of fifteen TYLCV resistant/tolerant commercial tomato hybrids during the 2018 and 2019 fall season conditions to identify the best hybrids and F2 populations for commercial production. Both F1 and F2 populations were evaluated separately for TYLCV resistance, yield, and fruit quality traits. Broad sense heritability (h2b) values of TYLCV resistance were high, being > 60% in hybrids 186, Goldstone, Rabha, SV0922 and SV8320 in both seasons. F1 and F2 populations of ‘186’, ‘Dania’, ‘PS550’, ‘Rozalina’, ‘SV0922’, ‘SV8320’, and ‘Tyrmes’ had the highest total yield (TY)/plant, low TYLCV disease (TYLCVD) mean scores, acceptable fruit quality traits, and average fruit weight > 80 g. Desirable inbreeding depression (ID) values were observed for TYLCVD mean score in F2 populations of most evaluated hybrids; for TY/plant in F2 populations of ‘SV3773’ in both seasons, and in populations of ‘186’, ‘448’, ‘Goldstone’, ‘Rabha’, ‘SV8320’ and ‘SV0922’ in the second season. Most hybrids had desirable significant ID values for fruit quality traits. Accordingly, it is concluded that the F2 populations of hybrids 186, SV0922 and SV8320 may be used in commercial tomato production under TYLCV infection conditions in fall season, as these populations recorded high h2 values for b TYLCV resistance trait and desirable ID for TYLCV resistance, yield, and fruit quality traits. During the 2019-2020 fall season twenty-three F3 plants, varying in yield and fruit quality and having low TYLCVD mean score, were selected. Thirteen out of them, viz., four F3 plants of ‘186’; 2 of each of ‘Tyrmes’, ‘SV8320’ and ‘SV0992’; and one of each of ‘Nariouz’, ‘65010’, and ‘Rozalina’ were chosen and selfed to produce seeds of F4 families.