COMPARISONS OF DURIAN FRUIT QUALITY BETWEEN F₁ HYBRID PLANTS AND THEIR PARENTS

A Durian Breeding program was conducted in Thailand at the Chanthaburi Horticultural Research Center, by making 55 crosses, between 1986-1990. 7,634 F₁ durian hybrid seedlings were produced. 2,743 F₁ hybrids were planted in the field and 330 F₁ hybrids have been grafted on bearing trees, to hasten flowering. Currently, some of them started bearing and were evaluated for fruit quality. Fruit quality measurements of 774 F₁fruits and their parents were carried out, using twenty-two different characteristics to compare these F₁ hybrids with their parents. It was found that there were substantial differences. Five characteristics viz. fruit weight, flesh thickness, percentage of flesh per fruit, eating quality (taste , aroma and texture) and percentage of aborted seeds are considered to be important to durian fruit quality and instrumental in the selection of F₁ hybrids. Eating quality was poorly correlated with fruit weight and flesh thickness. Flesh thickness and percentage of flesh per fruit were positively correlated with fruit weight. Percentage of aborted seeds was rather poorly correlated with fruit weight. Eighteen of forty-one promising F₁ plants have been selected as superior F₁ plants, on the basis that they produced good taste, had a fruit weight 2-4.5 kg, a flesh thickness of more than 0.70 cm, percentage of flesh per fruit more than 20 and percentage of aborted seeds more than 15. Another seven F₁ plants were also selected as they showed good eating quality but a percentage of aborteds seed of less than 15 or a percentage of flesh per fruit of less than 20. These F₁1 superior plants would be considered worthy of propagation by vegetative means and by selfing, to produce F₂ plants for further selection.