PEREFORMANCE OF POTATO GENOTYPES FOR MATURITY, LATE BLIGHT RESISTANCE, YIELD AND YIELD COMPONENT TRAITS IN EAST HARARGHE, ETHIOPIA.

Abstract

Development of potato varieties early maturating, resistant to late blight disease and high yield has vital importance in East Hararghe where potato is produced up to three cycles per year. Therefore, this research was conducted to evaluate potato genotypes for maturity, resistance to late blight disease and yield at three locations (Rare, Weter and Rare Hora). A total of 24 potato genotypes of which 4, 3 and 2 were farmers cultivars, improved and introduced varieties, respectively, were evaluated in randomized block design with three replications in 2018. The presence of significant differences among genotypes for all traits at three locations revealed from results of analysis of variance, location and interaction of genotype x location had also significant effects on most of traits. The early maturity genotypes had high bulking rate at harvest of 80 and 90 days after planting at locations where high tuber yield was obtained. Late blight appeared early on Seohong introduced variety and late on CIP-390010-10 on average at 36 and 73 days after planting, respectively. CIP-384321/3B and Seohong had 55.11% and 5651 highest disease intensity and AUDPC, respectively. CIP-390010-10 and CIP-387096-5 had 2.74% and 123 lowest disease intensity and AUDPC, respectively. Five genotypes evaluated as highly resistant, 8, 3 and 8 genotypes were resistant, moderately resistant and susceptible to late blight, respectively. The high yielding Bubu variety produced 23.99 to 35.73 and 22.48 to 34.55t ha-1 of total and marketable tuber yield, respectively, across three locations. Three genotypes at each location produced 2.32 to 34.77 and 8.02 to 40.19% higher total and marketable tuber yields, respectively, than Bubu variety across three locations. The genotypes had 1.07 to 1.099, 18.24 to 24.44% and 11.74 to 17.49% tuber specific gravity, dry matter and starch content, respectively, in which the highest and lowest mean values registered for Bubu variety and farmers’ cultivar, Dedafa. . A total of 5, 6 and 7 genotypes attained >80% total tuber yield of final harvest at 80, 90 and 100 days after planting across three locations, respectively. The lowest bulking rate (0.271g/day) estimated for Seohong at Weter at harvest of 120 days after planting and highest (17.39g/day) was estimated for CIP-391058-558 at harvest of 80 days after planting at Tinke. Moreover, CIP390010-10 and CIP391058-558 had 6 to 22.52% yield advantages over high yield check variety (Bubu) also had acceptable tuber specific gravity, dry matter and starch content across locations. These genotypes were evaluated as highly resistant to late blight. The two genotypes also attained 80 to 85% total tuber yield of final harvest 80 days after planting across locations and considered as early maturing genotypes. Therefore, it is concluded that these genotypes and other genotypes identified as early maturing, late blight resistant and had as equal or higher tuber yield than high yielding variety can be evaluated over many locations to develop varieties of farmers’ interest in the region