GROWTH AND DEVELOPMENT OF BARLEY AND WHEAT

Abstract

Variation in seedling leaf area characteristics and of development stages among barley and wheat genotypes and between species were
studied in a field experiment in the Winter-Spring season 1999-2000 (FEWS) and in a greenhouse in the Summer-Fall season 2000 (EGSF)
at Montecillo, Edo. de Mexico. Seven F₆ lines and three commercial varieties of barley and wheat were used in a complete randomized
block design with four replicates. In the FEWS, leaf area ratio (LAR, 0.18 cm² g^-1) and specific leaf area (SLA, 0.25 cm² mg^-1), averaged over all genotypes, were lower than EGSF (LAR, 0.35 cm² g^-1 and SLA, 0.48 cm² mg^-1). Growing degree days (GGD) to reach floral initiation (FI, 352 ºCd), terminal spikelet (TS, 623 ºCd ) of wheat or maximum number of primordia (MNP) of barley and anthesis (A, 1320 ºCd) were higher in the FEWS than EGSF (FI, 221 ºCd; TE or MNP, 325 ºCd; A, 839 ºCd), whereas GDD to reach physiological maturity (PM, 2003 ºCd) and commercial maturity (CM, 2211 ºCd) were lower in the FEWS than EGSF (PM, 2100 ºCd and CM, 2451 ºCd). Barley genotypes had higher LAR (0.21 cm² g^-1) and SLA (0.29 cm² mg^-1) than wheat (LAR, 0.15 cm² g^-1 and SLA 0.21 cm² mg^-1) in the FEWS; the same was observed in the EGSF (barley: LAR, 0.37 cm² g^-1 and SLA, 0.53 cm² mg^-1; wheat: LAR, 0.32 cm² g^-1 and SLA 0.43 cm² mg^-1). The faster leaf area growth and shorter duration to development stages, could be useful for breeding genotypes of either barley or wheat with a greater capacity to reduce direct soil evaporation losses in early crop stages of growth.