Leaf Anatomical Characteristics in Relation to Grain Yield of Wheat ( Triticum aestivum L.) Cultivars
An experiment was carried out to study the variability of leaf anatomical characters of wheat ( Triticum aestivum L.) cultivars and their association with grain yields. Results indicated that in most of the cases cultivar differences were significant. In respect of 6th leaf anatomical characters, simple correlation coefficients indicated that most of the leaf anatomical traits had significant negative relation with grain yield whereas in respect of flag leaf anatomical traits, only the association between radial dimension of big xylem vessel and grain yield was significantly negative and the correlation between number of veins and grain yield was significantly positive. Key words: Leaf anatomy, wheat, yield, correlation Â  doi: 10.3329/jbs.v15i0.2156 Â  J. bio-sci. 15: 153-158, 2007
Evaluating drought resistant wheat cultivars based on stem anatomical characteristics.
Water stressed have vital effect on the various anatomical, physiological and bio-chemical processes, which are controlled by genetic and prevailing environment. In present study, 25 wheat (Triticum aestivum L.) cultivars, which have been released over 40 years in Iran, were evaluated in terms of stem physiological and anatomical changes at Iran Agricultural Research Station. During growing season data were collected and finally crop was harvested in June and various anatomical aspects like Thickness of stem (TS), Thickness of fiber (TF), Tangential dimension of collenchymas cells (TDC), Tangential dimension of vascular bundle (TDVB), Radial dimension of vascular bundle (RDVB), Radial dimension of big xylem vessel (RDBXV), Tangential dimension of phloem bundle (TDPB), Distance between vascular bundle to Epidermis (DBVBE), Thickness of epidermal cell (TE) that are integral part of drought resistance were studied. Predominantly drought resistant genotypes were recorded with anatomical aspects which play major role in imparting drought resistance. Among the studied 25 genotypes, genotype number 7, 21 and 25 showed maximum drought resistance characteristics collectively and these can be used as parent cultivars for future breeding programs. KEYWORDS
Effect of Soybean Cyst Nematode (Heterodera glycines) on Yield of Resistant and Susceptible Soybean Cultivars Grown in Ohio.
Soybean (Glycine max) producers in Ohio rarely use soybean cyst nematode (Heterodera glycines, SCN)-resistant cultivars because of concerns over limited yield potential and lack of resistance to Phytophthora sojae. A two-year study was initiated to determine grain yield and nematode population increase on soybean cyst nematode-resistant cultivars in maturity groups II and III in production fields. Sites differed in soil texture, nematode densities, and P. sojae infestation at a number of locations in Ohio. Soil was assayed for nematode densities before planting and at harvest. Yields of resistant cultivars averaged 0% to 18% higher than those of susceptible cultivars in fine-textured soils with average preplant populations ranging from 463 to 14,330 SCN eggs/100 cm(3) soil. In coarse-textured soils, yields of susceptible cultivars were 21% to 56% less than the resistant cultivars with average preplant densities ranging from 1,661 to 15,558 SCN eggs/100 cm(3) soil. The reproductive index ranged from 0.1 to 5.5 for resistant cultivars and 0.4 to 112 for susceptible cultivars. In 1993, yield of P. sojae-susceptible, nematode-resistant 'Asgrow A 3431' was as high as yield of the P. sojae-resistant, nematode-susceptible cultivar 'Resnik' in a Phytophthora-infested field. The nematode-resistant cultivars Madison Experimental 131527 and Asgrow A3431 had higher yields than AgVenture AV1341 and susceptible cultivars Resnik and Kenwood when compared over five nematode-infested sites. Nematode-resistant cultivars were found to be excellent alternatives to currently grown susceptible cultivars for managing SCN where group III cultivars are used. However, better cultivar alternatives may be needed for sites with combined Phytophthora root rot and cyst nematode problems.