Three varieties of waxy corn, which were Chainat waxy corn 84-1, Fancy 111 Purple waxy corn and Boukgeen4 were studied on the effect of chitosan liquid fertilizer with ammonium sulfate (21-0-0) and control (ammonium sulfate; 21-0-0) on growth. The experimental design was randomized complete block design (RCBD) with three replications. Waxy corn seeds were sowed directly in the field with spacing of 30 × 30 cm. Chitosan liquid fertilizer was sprayed to seedling at 15 days old after seeds germination and every weeks. A dilution, 1: 1000 of chitosan liquid fertilizer was sprayed to plant every weeks.
The improvement of waxy corn used self-pollination and cross-pollination. Preparation of female inflorescences by using paper bags covered stigma male and female inflorescences before pollination. Breeding used hand pollination and repeated pollination for 5 day. Ears were harvested when the silk turned to brown.