Effect of sowing date on fusarium head blight severity in some promising lines of wheat in Moghan, Iran

Abstract

In order to examine the effects of sowing date of wheat cultivars and lines on fusarium head blight (Scab) (FHB), a study was carried out as a split-plot experiment based on a randomized complete block design with 3 replications. FHB is a serious problem in wheat fields of Northern provinces as well as Moghan, Iran. It seems that wheat spikes are sensitive to FHB in a short part of their growth period which can serve as an ideal opportunity for controlling FHB through changing sowing date and the resulting change in spike-bearing time. In this study, five wheat cultivars including Tajan, Falat and promising lines of N-80-6, N-80-19, N-78-14, N-80-7 and N-81-18 were studied at 4 sowing dates of November 6, 11 and 26 and December 11 in growing season of 2007 to 2008. The main plots including sowing date and the sub-plots included different cultivars. Days to spike-bearing, days to physiological maturity, infection plants percentage at each sowing date, grain yield, 1000-grain weight, spike length, number of spikelets and number of grains per spike were measured on quintuple randomized sampling. The modified method of Irta and Gilchrist and disease index were used for assessment of FHB. The results showed significant differences in days of spike-bearing and days of physiological maturity between sowing dates at 0.01 probability level. The cultivars exhibited significant differences in their spike length, grain weight per spike and 1000-grain weight at 0.01 probability level. In addition, cv. Falat suffered from the highest damage with FHB disease index of 70% at sowing date of November 6, so that it was selected as the most sensitive cultivar to FHB with mean disease index of 40%. Furthermore, cv. Tajan and lines N-80-18, N-80-7, N-78-14 and N-81-18 can be grown in region as semi-tolerant cultivars at sowing dates of November 6, 11 and 26. Also, the studies showed that tolerant cultivars can be planting from November 11 until November 26, so that this period is best sowing period for avoiding wheat FHB in Moghan, Iran. Moreover, N-81-18 was found to be the best line among studied cultivars and lines with disease index of 2.5% and yield of 73202 kgha-1. Key words: Wheat, sowing date, fusarium, cultivar, line.