EVALUATION OF EXPERIMENTAL HYBRIDS WITH THEIR PARENTS IN TOMATO (Solanum lycopersicum L.)

Abstract

The experiment under the investigation was conducted at Plant Breeding Research Field, HSTU, Dinajpur during winter season of 2014-2015. The experiment was laid out in Randomized Block Design with three replications. There were seven parental lines and twenty one hybrids. The tomato hybrid seeds with their parents were sown on 15th October, 2014 and then 25 days old seedlings were transplanted providing the spacing of 80cm x 50cm. Plant protection measures and intercultural operations were carried out as and when necessary. The mean performances of different characters were separated by Duncan Multiple Range Test (DMRT), where the highest yield/plant (5.70 kg) was recorded from the cross LE1 x LE7 (Madhobi x Apurba) and it was statistically alike with the yield/plant (5.33 kg) obtained from the cross, LE1 x LE2 ( Madhobi x Ratna). The analysis of variance and analysis for combining ability indicated significant variation among the parents and hybrids for most the selected characters. Positive and significant GCA effects were shown by the parents like Madhabi, Ratna, Chraboni and Shila. The parents showing positive and significant GCA effects indicated high crossability with all parents and genetics on the expression of the characters predominantly would be additive. Out of 21 experimental hybrids, four crosses viz, LE1 x LE2 (Madhobi x Ratna), LE1 x LE7 ( Madhobi x Apurba), LE2 x LE4 ( Ratna x Anupoma) and LE4 x LE7 (Anupoma x Apurba) exhibited positive and significant SCA effects for yield/plant due to exploitation of non-additive (dominance and/or epistasis) interaction of genes. Hybrid vigor is the interaction output of non-allelic interactions, hence the four cross combinations viz, LE1 x LE2 (Madhobi x Ratna), LE1 x LE7 (Madhobi x Apurba), LE2 x LE4 (Ratna x Anupoma) and LE4 x LE7 (Anupoma x Apurba) invariably to be promising for improvement of yield in tomato though hybrid breeding. The external expression of heterosis is the hybrid vigor, heterosis was estimated over the better parent (heterobeitiosis) and average heterosis (heterosis over the mid parent) against of all the selected characters. Heterobeltiosis invariably is better than average heterosis but two parental contributions are equally beneficial than average heterosis may be considered. Among the 21 hybrids, two combinations like LE1 (Madhobi) x LE2 (Ratna) and LE1 (Madhobi) x LE7 (Apurba) showed exhibited positive and strongly significant heterobeltiosis for yield/plant. Besides, another three combinations viz. LE1 (Madhobi) x LE3 (Chraboni) and LE3 (Chraboni) x LE5 (Jhuma) and LE1 (Madhobi) x LE7 (Apurba) showed positive and significant average heterosis for yield/plant. Therefore, six parental lines such LE1 (Madhobi), LE2 (Ratna) LE3 (Chraboni), LE4 ( Anupoma), LE7 (Apurba) should be maintain generation after generation to ensure constant supply of parental lines in hybridization programs and in addition, the outstanding high yield potential above mentioned five hybrids may be advanced for commercial cultivation by the farmer‟s of our country.