Scilight Press

In order to select the drought resistance for the new king orange seedless, the prominent local king orange was collected from the area under the shortage of irrigation water in dry season at the Mekong delta region in southern Vietnam. The experiment was carried out under the actual field conditions at Cau ke dist, Tra Vinh province in two lots. A lot was the drought treatment condition and the other, four meters apart, was the checked lot, followed in the randomized block design with the 12 replications. One plant for each genotype was exposed to drought stress by withholding irrigation for 30 days in the dry season, March 2020. Based on the response ability of king orange seedless plants in drought, salty stress under field conditions compared with the control (not stress), there was no reduction in total chlorophyll content 10.83 mg/dm² , chlorophyll fluorescence of phytosystem II (0.63), soluble sugars (154 mg/g), proline in leaves (5.6 mg/dg), plant height (154.08 cm), stem diameter (5.6 mm), wilting index (71.6%) of the leaf set, the king orange seedless had a better tolerance to natural drought in the field for 30 days when the plant reached growth 48 months after planting than the local king orange variety. The king orange seedless variety with good quality by planting model with appropriate farming techniques (new varieties, appropriate water distribution, reduced chemical fertilizers and increased organic fertilizers) and effective net profit of VND 250,074 million was accepted by the people.