EVALUATION OF HYBRIDS FROM EIGHT PROCESSING TOMATO LINES RESISTANT TO TOMATO SPOTTED WILT VIRUS

Eight processing tomato lines homozygous for the Sw-5 gene that confers resistance to Tomato spotted wilt virus, were obtained in a breeding program. The recurrent parent used to obtain lines 1, 2 and 8 was the processing tomato ‘FM-6203’ (‘FM-6203’ was substituted for the processing tomato ‘Gévora’ after the second backcrossing cycle). The recurrent parent used to obtain lines 3 and 4 was the processing tomato ‘H-324-1’ and the recurrent parental used to obtain lines 5, 6 and 7 was the processing tomato ‘Peelmech’. Using hybrids of these lines, specific and general combining ability was tested in 2003 in a trial located in Las Vegas del Guadiana (Badajoz, Spain). No significant differences were detected between hybrids for commercial yield, but there were differences in precocity, plant size, fruit firmness, fruit coverage by leaves, percentage of imperfect fruits (differences were detected for the defects: blossom end rot, fruit diameter less than 40 mm, fruit harvested with the peduncle, and sunscald). In spite of the differences observed, more than a half of the tested hybrids had from medium to high specific combining ability. The general combining ability study showed that there were only a few differences between the eight processing tomato lines. These differences were enough to detect that line 3 had the best general combining ability for yield, because hybrids produced from it achieved 107±7 t/ha of commercial yield average. Furthermore, lines 4, 7 and 8 had the best general combining ability for quality because hybrids produced from them achieved 5.1±0.1, 5.2±0.1, and 5.1V0.1 °Brix on average respectively.