The objective of current study was to look at the variable expression of antioxidant enzymes in wheat genotypes exposed to various water stress regimes. Further the malondialdehyde (MDA) content were measured as an indicative of membrane integrity. Tolerance indices were calculated which reinforce in distinguishing tolerant and susceptible genotypes. The experimental material consisted of thirteen genotypes obtained from different sources. Stress was imposed by withholding irrigation at three different growth stages of plant, i.e. tillering, anthesis and grain filling. Four resistance indices include stress susceptibility index (SSI), yield stability index (YSI), mean productivity (MP) and tolerance index (TOL) was calculated on the basis of grain yield. Water stress treatments had no significant effect on CAT activity. CIM-47, CIM-49 and NR-234 showed minimum MDA content with increased POX activity under three different irrigation conditions and are therefore considered as tolerant genotypes. Higher levels of MDA with decline activity of POX was found in CIM-51, DD-4 and NR-230 led to suggest them as susceptible genotypes. The variable response of genotypes in tolerance could be related to differences in antioxidant enzyme levels. Significant positive correlation was found between SSI and TOL values whereas negative and significant association was noted between SSI and YSI. Significant and negative correlation was observed between YSI and TOL values. These traits are recognized as beneficial water stress tolerance indicators for selecting a stress tolerant variety. The most outstanding tolerance capacity in terms of susceptibility indices was detected in CIM-47 and CIM-50 under all water stresses. They indicated lowest SSI, TOL and MP with high YSI values. It may, therefore, be concluded that these genotypes have the potential of stress tolerance.
Authors:A. Limon-Ortega, E. Villaseñor-Mir, and E. Espitia-Rangel
L.) grain production in the Central Highlands of Mexico occurs under rainfed conditions. Traditionally this crop has been planted by conventional means in solid stands combined with heavy tillage and lack of ground cover. These practices have been leading to soil erosion in the sloping lands, frequent drought stress, and water logging after occasional heavy rainstorms in the low lands. To ameliorate those constrains, farmers have started to replace the traditional planting system by the planting system on narrow raised beds. However, information on N management and varieties is needed. This 5-yr study was conducted from 1999 to 2003 to test a set of eight wheat genotypes using a raised-bed system to evaluate their performance as affected by N fertilizer management. Three N rates (40, 70 and 100 kg N ha
) were applied at planting, at the end of tillering-early jointing, and split at planting and at the end of tillering-early jointing. Treatments included an unfertilized check plot. Results indicated that the optimum N fertilizer rate for wheat grain production varies from 0 to 40 kg N ha
) depending upon the variety. Nitrogen timing practices had no effect on grain yield but on N use efficiency (NUE). The split application of 40 kg N ha
increased the NUE. Higher N rates reduced the NUE irrespective of the N timing practice. According to the differential performance among varieties, this study showed that the planting system on narrow raised beds is a variety-specific technology. The relative grain yield, stability, and NUE, indicated that Tlaxcala F2000, Nahuatl F2000 and Romoga F96 are the most adequate varieties for the planting system on narrow raised beds in the Central Highlands of Mexico.
Berzsenyi, Z., Győrffy, B. (1995): Különböző növénytermesztési tényezők hatása a kukorica termésére és termésstabilitására. (Effect of various crop production factors on the yield and yieldstability of maize.)
talajjavításához és tápanyagellátásához — Növénytermelés Vol 55 Nos 3–4
Pepó, Péter, Győri, Z.: 2005. A Study of the YieldStability of Winter Wheat Varieties — Cereal Research Communications, Vol. 33 No. 4 pp. 769
Authors:Marcin Kozak, Dariusz Gozdowski, and Zdzisław Wyszyński
García del Moral, L., García del Moral, M., Molina-Cano, J., Slafer, G. (2003). Yieldstability and development in two-and six-rowed winter barleys under Mediterranean conditions.
Field Crops Res.