Field evaluation of true potato seed progenies in the Philippines

True potato seed progenies from diverse genetic backgrounds were evaluated in three environments, both as transplants and as first generation seed tubers. Plant growth from transplants was extremely sensitive to daylength and temperature. The mid-elevation site with minimum/maximum temperatures of 17/27 C and a 12 to 12.7 h daylength favored rapid canopy growth and acceptable tuber yields (up to 28 t/ha) for most progenies evaluated. Under cooler, shorter, daylength growing conditions, seedlings would tuberize rapidly, particularly those of a predominatelyS. tuberosum L. background. Tuber yields from transplants generally were much lower than those from the local cultivar grown from seed tubers but had many more tubers, which is favorable as an efficient way to produce seed tubers for replanting. First generation seed tubers had superior yields compared to transplants, especially at the high and low elevation locations and gave yields similar to the local cultivar. On the basis of tuber yield, tuber size and uniformity of TPS progenies, the following are some of the superior parental lines: I-931, I-1035, CFK69.1, Atzimba, Serrana, LT-7, 7XY.1, (BR63.74x Katahdin) .7 and .9, 378015.3 and .16.