Nebraska winter wheat unexpected flowering in Egypt: New improvement opportunities

Abstract

The University of Nebraska has bred some of the most winter hardy wheat (Triticum aestivum L.) cultivars in the United States. With the advent of a new race of stem rust in Africa, the breeding program identified a testing site in northern Egypt, a Mediterranean environment, for seedling disease resistance screening. Quite surprisingly, the Nebraska winter wheat lines flowered when grown in northern Egypt, indicating the lines were vernalized. To confirm this result, a panel of 112 Nebraska winter wheat genotypes and three commercially grown Egyptian spring wheat check cultivars were grown in three replicates in a randomized incomplete block design at two locations for 3 years (2016/2017-2018/2019) in Egypt. Seven traits were measured on all genotypes (the number of days to flowering; total chlorophyll content; plant height; leaf, stem, and stripe rust reaction; and grain yield). The winter wheat genotypes flowered and several of them were not significantly different in grain yield from the spring cultivars. A multi-trait stability index identified 22 genotypes (20% selection intensity, the local checks, and 19 lines from the United States) for good performance. This study provides novel evidence that winter wheat can flower in northern Egypt, can be used for adult plant resistance screening, and provide a grain yield comparable to the commercially grown spring wheat cultivars. Our findings are expected to facilitate future efforts to hybridize winter-by-spring lines to develop new genotypes with ANOVA, analysis of variance; BLUP, best linear unbiased prediction; CIMMYT, International Maize and Wheat Improvement Center; GEI, genotype by environment interaction; GY, grain yield; LR, leaf rust; ME, mega-environment; MET, multi-environment trial; MTSI, multi-trait stability index; NDF, number of days to flowering; PCA, principal component analysis; PH, plant height; SPAD, soil plant analysis development; SR, stem rust; WAAS, weighted average absolute score; YR, yellow rust.