The present investigation was carried out under insect-free cages during the three successive seasons 2004-2006. A diallel cross excluding reciprocals among eight faba bean genotypes was used to estimate the heterotic effects of F₁ crosses and F₂ populations relative to their respective mid and better parents and combining ability analysis for yield and some of its variables. Highly significant differences among the tested entries were detected for different traits, indicating wide genetic variability for all traits. Heterosis percentages relative to mid-parents were significantly positive in several crosses with a range of 15.6-19.7, 38.0-59.8, 85.0-131.4, 74.3-79.4, 54.4-127.2 and 69.8-142.0% for plant height, number of branches per plant, number of pods per plant, number of pods per main stem, number of seeds per plant and seed yield per plant, respectively. However, heterosis percentages relative to better parent were significantly positive in some crosses and recorded a range of 19.0-19.0, 54.2-73.7, 62.9-97.7 and 47.6-129.9% for plant height, number of pods per plant, number of seeds per plant and seed yield per plant, in the same order. Some crosses exhibited significantly negative heterosis compared to respective mid-parent for days to flowering (from -9.0-23.5%). The ratios of <img src="../xml/ajcs/2009/images/img1-2k9-2058.gif" width="47" height="18" align="absmiddle"> exceeded the unity for number of pods per plant, number of pods per main stem and 100-seed weight indicating that the genetic variation among these traits appeared to be additive. However, low <img src="../xml/ajcs/2009/images/img1-2k9-2058.gif" width="47" height="18" align="absmiddle"> (less than unity), revealed the predominance of non-additive gene action for days to flowering, plant height, number of branches per plant, number of seeds per plant and seed yield per plant. The three parental genotypes: Aquadulce, Luz and Giza 716 were found to be a good combiners for 100-seed weight. Moreover, the parental genotype Geizera 2 was a good combiner for both number of pods and seed yield per plant. Three parents Geizera 2, Giza 402 and Triple white were good combiners for earliness. Five crosses Geizera 2xGiza 716, Geizera 2xSakha 1, Geizera 2xGiza 402, Giza 716xSakha 1 and Giza 716xGiza 402 had significant Specific Combining Ability (SCA) for most studied traits.

SCA --- GCA --- gene action --- mid-parents --- heterosis --- Diallel --- faba bean

The effects of foliar and soil application of humic substances on plant growth and some nutrient elements uptake of wheat (Triticum durum Salihli) grown on various salt concentrations were examined. Sodium chloride was added to soil to obtain 15 and 60 mM saline conditions. The solid humus was applied to the soil one month before planting and the liquid humic acid was sprayed twice on the leaves on day 20 and 35 after seedling emergence. The application doses of solid humus were 0, 1 and 2 g kg^-1 and the liquid humic acids were 0, 0.1 and 0.2%. Salinity negatively affected the growth of wheat; also decreased the dry weight and the uptake of nutrient elements except for Na and Mn. Soil application of humus increased the N uptake of wheat and foliar application of humic acid increased the uptake of P, K, Mg, Na, Cu and Zn. Although the effect of interaction between salt and soil humus application was found statistically significant, the interaction effect between salt and foliar humic acid treatment was not found significant. Under salt stress, the first doses of both soil and foliar application of humic substances increased the uptake of nutrients.

soil application --- salinity --- humus --- humic acid --- Foliar application

Field experiment was carried out to evaluate the nitrogen efficiency and nitrogen response under no nitrogen application and nitrogen application conditions. The differences of grain yield, nitrogen absorption amount, nitrogen response and nitrogen use efficiency among 16 winter varieties of oilseed rape (Brassica napus L.) were systematically studied and the contribution of nitrogen absorption efficiency and nitrogen use efficiency to nitrogen efficiency in different oilseed rape varieties were preliminarily discussed. Results showed that, the differences of grain yield, nitrogen use efficiency and nitrogen response among the 16 oilseed rape varieties were significantly, regardless of N application level; but only under no N application conditions, the differences of nitrogen absorption amount among varieties were significantly. The 16 oilseed rape varieties were divided into four different genotypes in accordance with the nitrogen use efficiency and nitrogen response under no nitrogen application condition: (1) Nitrogen High Efficiency-Nitrogen High Response, included Xy1, Xy16, Xy17, Xh19, Xh20 and Xy21. (2) Nitrogen Low Efficiency-Nitrogen Low Response (NLE-NLR), included Xy6, Xy8 and Xy9. (3) Nitrogen High Efficiency-Nitrogen Low Response (NHE-NLR), included Xy7, Xy12, Xy14, Xy15 and Xy24. (4) Nitrogen Low Efficiency-Nitrogen High Response (NLE-NHR), included Xy11 and Xy13. The variation coefficient of nitrogen use efficiency was higher than nitrogen absorption efficiency, regardless of N application level; it was also showed that the contribution of nitrogen use efficiency to nitrogen efficiency was higher than nitrogen absorption efficiency. However, variation coefficient of nitrogen absorption efficiency under nitrogen application condition was higher than under no N application condition; variation coefficient of nitrogen use efficiency was reverse. It was indicated that, under no N application condition, the variation of nitrogen efficiency because of nitrogen use efficiency was decreased and variation of nitrogen efficiency because of nitrogen absorption efficiency was increased.

nitrogen use efficiency --- nitrogen response --- nitrogen efficiency --- Oilseed rape (Brassica napus L.) --- N application level --- yield