TANGGAPAN DUA PULUH KLON KENTANG (Solanum tuberosum L.) TERHADAP SUHU TINGGI PADA KONDISI IN VITRO DAN LAPANGAN

Productivity of potato plants hampered with high temperature or heat stress, with the yield losses up to 32%. Therefore, in order to increase the potato growing in lowland area, adaptive and tolerant cultivars to heat stress are required. This research aimed at determining (1) responses of morphological characteristics of plant and tubers, as well the decreasing of tuber productivity due to high temperature, and (2) heat tolerance level of 20 clones based on tuberization ability. Twenty clones of potato were used in this research. Observation included membrane stability testing, in vitro testing at normal temperature (20 °C) and high temperature (27 °C) towards chlorophyll content, vegetative growth, microtuberization, and microtuber production, and field testing in Margahayu Field Station, Lembang for normal temperature condition and Wera Field Station, Subang for supraoptimal temperature condition. Membrane stability testing showed that variation in cell membrane injury rate of the clones tested were in accordance with the information about their respective tolerance to high temperature. The responses of the potato clones to high temperature at in vitro conditions included reduction of leaf chlorophyll content, elongation of nodes, diminishing of leaf size, decrease in vigor, reduction in the intensity of stem and leaf green color, and inhibition of the production of microtuber and forming of shoots at the micro-tubers. Clones CIP 394613.139, CIP 394614.117, CIP 395195.7, and �GM 08� could be categorised as heat tolerant. High temperature condition in field trial gave similar effects as in in vitro condition, with the addition to reduction of tuber number and size per plant. Changes in plant and tuber morphology were also detected, such as more upright growing habit, elongated stem, decreasing leaf size and tuber size, and formation of tuber knobs. Clones �Atlantik M�, CIP 395197.7, N.1, and �Ping 06� could be categorised as tolerant to high temperature under field conditions. CIP 395195.7 was the only clone that performed heat tolerance in both in vitro and field conditions. No significant correlations were observed between in vitro and field production characters