Effect of osmopriming sources and moisture stress on wheat

Wheat yield in Pakistan is very low due to poor germination and poor stand establishment and optimum amount of water availability at critical growth stages. To cope with these problems experiments were planned including control and nine osmopriming sources per liter of water that is PEG (100 g), KCl (37.25 g), KNO/sub 3/ (101 g), NaCl (58.5 g), NH/sub 4/ Cl (53.5 g), CaCl/sub 2/ (55.5 g), Mannitol (20 g), Na/sub 2/ SO/sub 4/ (71 g) and hydro priming. In the filed these were studied at three moisture stresses of 60, 70 and 80% MAD (management allowable depletion). The experiments were repeated during 2008 and 2009 and were laid out in randomized complete block design with split plot arrangement replicated three times. Moisture stress was allotted to main plots and osmopriming sources to sub plots. Best combinations of moisture stress (M) and osmopriming sources (OPS) significantly affected pheno logical and grain yield components of wheat. Increased moisture stress showed decreased pheno logical life of the wheat. Hence lowest days to maturity (157.1) were noted for 80% MAD. The optimum MAD (70%) contributed to maximum grain yield (3348.6 kg ha/sup -1/). Wheat showed variation in response to osmopriming sources. Minimum days to emergence (8.1) were noted for PEG. While KNO/sub 3/ osmoprimed seeds took lowest days to maturity (155.4). Highest emergence m/sup -2/ (82), thousand grains weight (39.97 g), and grain yield (3481 kg ha/sup -1/) were recorded for PEG (100 g L/sup -1/ of water). Likewise KNO/sub 3/ (101 g L/sup -1/ of water) osmoprimed seeds attained highest number of grains spike/sup -1/ (51.0). From this study it was concluded that wheat seeds may be osmoprimed with PEG, Na/sub 2/ SO/sub 4/, KNO/sub 3/, CaCl/sub 2/ and water along with the application of 70% MAD irrigation at critical growth stages for gaining high yield. However, due to the high prices of PEG and other osmopriming sources in the market hydro priming is recommended for gaining high net benefit and income. (author)