Can Predicting Soft Red Winter Wheat Development Assist Agronomic Management in Kentucky?.

Soft red winter wheat (SRRW) is an important crop in Kentucky. The ability to predict the occurrence of developmental stages could improve agronomic management of SRRW in Kentucky, particularly as climatic variability increases. However, predicting developmental stages in SRRW is complex due to differences in photoperiod sensitivity and vernalization requirement. To develop an estimate of thermal time required by wheat to reach management specific growth stages in Kentucky field experiments were conducted during the 2016 and 2017 growing seasons. Fifty soft red winter wheat cultivars were seeded into hill plots monthly from October to March. The date of key developmental stages important for agronomic management were measured: date of emergence (Feekes 1), tillering (Feekes 3), pseudostem erection (Feekes 5), jointing (Feekes 6), flag leaf (Feekes 9), beginning flowering (Feekes 10.5.1), full flowering (Feekes 10.5.3), and harvest maturity (Feekes 11.4). Total number of kernels, total kernel weight, 1000 kernel weight, and number of spikes per plot were also measured. In order to identify the relative vernalization requirement of the 50 SRRW lines, seeds were germinated in a glasshouse and seedlings were vernalized for 3, 6, or 9 weeks in the field. After this time, the seedlings were moved back to the glasshouse and date of Feekes 10.5.3 was measured. We also examined whether genotype is an accurate predictor of field phenotype by characterizing the 50 lines at fourteen VRN and PPD loci using Kompetitive Allele Specific PCR (KASP) markers. The results of these studies will be discussed.