Abstract

Spring wheat is a widely planted crop in Qinghai Province of Northwestern China, where drought acts as a major bottleneck for stable production. However, responses of wheat to moisture deficit remain unclear in this region. Experiments of 60 spring wheat cultivars in randomized complete bock design with three replications were carried out to determine effects of moisture deficit on 11 morphological traits under normal irrigation and drought stress at Ping’an Ecological Agriculture Station, Qinghai province, China. The results showed that all the morphological traits except plant height (PH) were significantly influenced by water condition. Internode length under spike (IL), tillers per plant (T/P), spikelets per spike (S/S), fertile spikelets per spike (FS/S), and grain weight per spike (GW/S) were mainly affected by water condition and could be used as indexes of moisture deficit. Spike length (SL), distance of spike to flag leaf (DSL), kernels per spikelet (K/S), grains per spike (G/S), and 1000 grain weight (GW) were influenced by genotypes and their interaction with environments. Drought stress changed correlations among the morphological traits. The results of non-metric multidimensional scaling (NMDS) on morphological traits revealed that the 60 cultivars responded to moisture deficit similarly. The distance of cultivars in the same decade between normal irrigation and drought stress became larger with time, indicating that the current breeding program has enlarged the difference of cultivars to water-limited environment and it might reduce yield stability under high extreme drought frequency in the future.

Key words: Yield-related characteristic, general linear model, non-metric multidimensional scaling, drought stress, spring wheat.