Breeding tomato for cold, heat tolerance and for long-shelf life

Improvement of three heat tolerant tomato varieties: L 22, 598 (CL5915-2-5-1-1) and 607 (CL5915-223-2-1-0) for long-shelf life of fruit. Mutant genes nor 1 and 2 were sued. Hybrids between the heat tolerant varieties and the mutant varieties were backcrossed to their recurrent varieties. Backcrossed progenies of the second and the third generations to variety L 22 showed 4-9 percent higher yield and longer shelf-life of fruit than variety L22. When fruits were kept at room temperature for 30 days, the 2nd and 3rd backcrossed progenies had 18-38 percent good fruits while variety L 22 had none. Backcrossed progenies of the second and third generations to variety 598 showed 15-54 percent higher yield and longer shelf-life to fruit than variety 598. The same results were obtained in the 2 nd and 3 rd backcrossed progenies of variety 607. They showed 23 percent higher yield and longer shelf-life of fruit than variety 607. Two heat tolerant varieties: 667 (CL 5915-206 D 4-2-5-0) and 669 (CL 5915-223 D 4-2-1-0) were crossed to heat tolerant and winter tomato varieties. They were selfed and selected for several generations for heat tolerant and good fruit qualities. Some selected varieties from crosses 502 x 669 and 574 x 667 showed higher yield than control varieties: Lima and VF 134-1-2. The yields of the selected varieties were 11,065.6 and 10,585.6 kg/rai while the control varieties were 9,361.6 and 7,980.8 kg/rai, respectively. Fruit firmness of the selected varieties was as good as the control varieties. Winter tomato varieties were improved by using variety Lima as a male parent to cross to some recurrent winter tomato varieties: 413,452,499,514 and 560. Progenies of the hybrids were selected by pedigree method. The inbred lines of the crosses showed 12-32 percent higher yield than varieties: VF 134-1-2 and Lima. The inbred line from crossed 452 x 351 and 499 x 351 showed high yields, 7,086.4 and 6,934.3 kg/rai, respectively, while varieties Lima and VF 134-1-2 showed 5,385.6 and 5,326.4 kg/rai, respectively. Most of the inbred lines showed fruit firmness as good as the control varieties. Inbred line 499 x 351yielded secondly to line 452 x 351 and yielded 43.34 t/ha. When it was used as a testing variety at Ban Maekung and Ban Hankaew around the outskirt of Chiang Mai, adopted the line for production.