Cucurbit Genetics Cooperative Report 20:65 (article 29) 1997
Regeneration of Plants from Hypocotyl of Sechium edule Swartz
Xiaosou Wang, Buxun Li and Guangdong Wang
Northwestern Agricultural University, Yangling, Shaanxi, China
Buddha's Hand (Sechium edule) is a perennial root vegetable suitable for cultivation in tropical and sub-tropical regions. It is grown in southern and Southwest China where it has been readily accepted by farmers because of its high tolerance to disease, tolerance to storage and transportation, and high economic value. In recent years the crop has been successfully introduced into Northern China. However, production throughout all of China is limited by low propagation efficiency and high seedling cost.
The purpose of these experiments was to develop methods to overcome the high propagation costs. Experiments were conducted at the Northwest Agricultural University during two seasons: December 1993 - June 1994; and December 1994 - November 1995.
Experiments were conducted to determine optimal media for plantlet regeneration from hypocotyl explants. Experiments were also conducted to determine media for initiation of shoots and roots from hypocotyl calli and from stems with terminal buds and stem segments with axillary buds.
The greatest induction of calli from hypocotyl tissue was obtained from MS medium supplemented with 0.1 mg/L IAA, 1.0 mg/L BA, and 200mg.L LH. Shoots were easily differentiated on MS medium with 0.5 mg/L IAA and 0.5 mg/L BA. The differentiation ratio was 575%. Differences were observed in optimal rooting media for shoots with terminal bud and shoots having axillary buds. Terminal bud segments rooted best in MS medium with 1 mg/L IAA, with rooting occurring in 8 days and at a ratio of 81.3%. Stem segments with axillary buds rooted at a ratio of 83.3%. Stem segments with axillary buds rooted at a ratio of 83.3% in 1/2 MS medium supplemented with 0.3 mg/L IAA. Rooting for these explants occurred in 5 days. Following rooting, plantlets were transferred to pots containing 3 parts soil, 2 parts sand, and 1 part manure. The survival rate for the transferred plantlets was 75%.
Plantlets were acclimated and hardened by initially keeping them in a small arched shed covered with plastic. In early May 1995, after 40 days acclimation, plants with 4 to 5 true leaves were planted in the field. the plants were still tender and required extra care to ensure survival. The plants flowered during the last 10 day period of October. Fruits were harvested on November 7, 1995. The average number of fruit per plant was 88.434 and the average weight was 240.2 g.