MSc

The project entitled “Development of hybrids with bacterial wilt resistance in tomato (Solanum lycopersicum L.)” was carried out at the Department of Olericulture, College of Agriculture, Vellayani, during 2015-2016 to develop F1 hybrids of tomato with high yield, quality and resistance to bacterial wilt.
The experiment was carried out in two parts. In part I, twenty one F1 hybrids were developed by crossing seven lines and three testers in a line x tester fashion in a crossing block. The seven lines consisted of high yielding genotypes identified and maintained in the department of Olericulture, viz., LE 3, LE 12, LE 13, LE 16, LE 19, LE 20 and LE 26 and the three testers were the bacterial wilt resistant varieties viz., Anagha, Manulekshmi and Vellayani Vijai. In part II, hybrids were evaluated along with their parents and checks (Indam 9802 and Lekshmi) during September 2015 – January 2016 in a Randomized Block Design with 33 treatments and three replications.
Analysis of variance revealed significant difference among the treatments for all the traits. Among the hybrids, LE 13 x Manulekshmi recorded the highest plant height (110.44 cm), LE 20 x Manulekshmi exhibited the highest primary branches plant-1 (12.55). The hybrid LE 16 x Anagha recorded early flowering (24.33), highest fruits plant-1 (110.66), yield plant-1 (2191.44 g), TSS (4.91%) and lycopene (13.03 mg/ 100 g). The cross LE 26 x Anagha had the highest fruits cluster-1 (6.33) and LE 13 x Vellayani Vijai recorded the highest fruit length (5.41 cm). The cross LE 13 x Manulekshmi was the best for fruit girth (15.07 cm) and yield plot-1 (31.42 kg), LE 19 x Manulekshmi for fruit weight (62.85 g) and LE 19 x Anagha for ascorbic acid (34.30 mg/ 100 g).
The estimates of general combining ability (gca) effects revealed that among the lines, LE 16, LE 13 and LE 20 were the best general combiners for fruits plant-1 while, LE 13 and LE 19 for fruit length, fruit girth and fruit weight. The lines LE 16 and LE 13 exhibited good gca for yield plant-1 and yield plot-1 while, LE 19, LE 13 and LE 16 for TSS and lycopene. For ascorbic acid, LE 19, LE 20 and LE 26 were the best general combiners. Among the testers, Anagha exhibited good gca effects for fruits plant-1, yield plant-1 and ascorbic acid. Manulekshmi was good general combiner for fruit girth, fruit weight and yield plot-1 while, Vellayani Vijai exhibited good gca for fruit length, TSS and lycopene content. The estimates of specific combining ability effects revealed that the hybrid LE 16 x Anagha was the best for fruits plant-1, yield plant-1, TSS and lycopene. Significant positive sca effect for fruits plant-1, yield plant-1, yield plot-1, lycopene and ascorbic acid was recorded in the cross LE 20 x Manulekshmi while, LE 26 x Manulekshmi followed by LE 19 x Anagha recorded high sca for ascorbic acid. The σ2gca and σ2sca ratio indicated preponderance of non additive gene action for bacterial wilt incidence (%).
Relative heterosis, heterobeltiosis and standard heterosis over checks were worked out for all yield and quality characters. The highest standard heterosis for fruits plant-1 (320.20% and 203.67% respectively), yield plant-1 (27.32% and 14.92% respectively) and TSS (16.89% and 13.91% respectively) was recorded in LE 16 x Anagha. Significant and positive standard heterosis for yield plot-1 was exhibited by LE 13 x Manulekshmi (220.03% and 125.01% respectively) while, LE 19 x Anagha for ascorbic acid content (41.06 and 24.24% respectively).
Based on bacterial wilt incidence (%), LE 13 x Manulekshmi, LE 16 x Manulekshmi and LE 20 x Manulekshmi were resistant with a disease incidence of 11.67%, 18.33% and 13.33% respectively. Other hybrids were in the range of moderately resistant to susceptible, while both the checks (Indam 9802 and Lekshmi) were susceptible with a disease incidence of 71.67% and 63.33% respectively.
Based on the mean performance, specific combining ability and standard heterosis, the hybrid LE 16 x Anagha was the best for fruits plant-1, yield plant-1 and TSS. The hybrid LE 20 x Manulekshmi was found promising for bacterial wilt resistance. Considering both yield plot-1 and bacterial wilt resistance, LE 13 x Manulekshmi was adjudjed the best.