Document Type : Original Article
Authors
1
Plant Res. Dept., Nuclear Res. Cent., Atomic Energ. Authority, Inchas, Egypt
2
Agron. Dept., Fac. Agric., Zagazig Univ., Egypt
Abstract
The present investigation was carried out at the Experimental Farm, Plant Research Department, Nuclear Research Center, Atomic Energy Authority, Inchas, Egypt during 2011/2012 and 2012/2013 seasons. Preliminary experiment was investigated to identify the proper dose radiation, seeds of the three cultivars (Sids 12, Sakha 94 and Gemmeiza 9) had been exposed to gamma irradiation doses of 0.0, 150, 200, 250, 300, 350, 400, 450 and 500 gray. Based on mean value of epicotyl length (cm), three gamma ray doses were selected i.e., 250 (Gy1), 300 (Gy2) and 350 Gy (Gy3) for both Sids 12 and Gemmeiza 9 cultivars as well as 350 (Gy1), 400 (Gy2) and 450 Gy (Gy3) for Sakha 94 cultivar. LASER treatments were 1, 1.5 and 2 hr., in addition to the control. The maximum values for both spike length and No. of fertile spikelets/spike were observed by Gemmeiza 9 which attained the lowest No. of sterile spikelets/spike (2.44). Furthermore, wheat cv. Sids 12 was the shortest height (75.19 cm) and gave the greatest No. of grains/spike (71.66) and the highest 1000-grain weight (41.27 g), while Gemmeiza 9 was the tallest (82.20 cm) and produced the greatest No. of spikes/plant (9.05) and grain yield/plant (14.79 g). Gamma irradiation dose (Gy1) resulted in a decrease in plant height (79.75 cm) and No. of sterile spikelets/spike (2.40) rather than the control. Grain yield/plant, No. of spikes/plant and spike length recorded significant increase due to gamma ray treatments at the lowest dose (Gy1) valued 14.42 g, 8.46 and 13.88 cm, respectively but both characters decreased with the highest dose (Gy3). LASER exposure periods at 1 hr., resulted in a significant increase in plant height and No. of fertile spikelets/spike, but significantly reduced No. of sterile spikelets/spike rather than 1.5 and 2 hr. Both 1.5 hr., and 2 hr., LASER exhibited significant increase in grain yield/plant valued 15.78 g and 15.57 g, respectively, rather than the control (13.67 g). Interaction of cultivar × mutagen treatments was significant for all studied wheat characters, except No. of fertile spikelets/ spike. Under gamma ray, GCV and PCV estimates were high for No. of spikes/plant only, with higher estimates of ECV for that character and grain yield/ plant. Whereas, it was relatively low for plant height, spike length, No. of fertile spikelets/spike and No. of sterile spikelets/spike. Heritability in broad sense was high (≥75%) for plant height, spike length, No. of sterile spikelets/ spike, No. of spikes/plant, No. of grains/spike, and 1000-grain weight. Estimates of broad sense heritability coupled with genetic advance and were low for No. of fertile spikelets/spike and grain yield/ plant. Estimates of GCV and PCV under LAZER ray were high for No. of grains/spike, 1000-grain weight and grain yield/plant, whereas, it was low for plant height, spike length and No. of spikes/ plant. These findings indicate the importance of previous results in wheat breeding programs for improving yield.
Keywords
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