Six population’s seeds of four yellow maize crosses were formed during 2001 and 2002 growing seasons. Their plants were evaluated during 2003 growing season under two planting dates (14th May and 29th June) for six agronomic traits at the Agric. Res. Stat. of Fac. of Agric., Ain Shams Univ., Shalakan, Kalubia Gover-norate, Egypt. The present work aimed to determine the genetic parameters and their interactions with planting dates for grain yield per plant, 100-kernel weight, number of kernels per row, ear length, ear diameter, and days to silking in the six popula-tions (P1, P2, F1, F2, BC1 and BC2). Mean values of the six populations for all studied traits in all crosses were higher under normal planting date than those under late one. Therefore, normal planting date seemed to be non-stress environment. The potence ratio for all traits in the four crosses exceeded (+1) except days to silking where it was less (-1). The highest heterosis percentage relative to mid and better parent reached 192.06% and 152.01% in cross 1 for grain yield per plant under late plant-ing date. Inbreeding depression values were not-significant in all studied traits ex-cept ear diameter and 100-kernel weight in crosses 1 and 3 as well as grain yield per plant in all crosses also, it was positive for most studied characters in the four cross-es except days to silking trait. Dominance occupied the first rank, additive or domi-nance type of epistasis occupied the second or the third contributor to the genetic ef-fects in order of importance according to cross with exception of days to silking, where additive and additive occupied the first and the second ranks. Narrow sense heritability was relatively high for yield attributes whereas it was low for grain yield per plant. Meantime, expected genetic advance was relatively moderate or low for all traits. Therefore, it could be suggested that selection for most studied traits in the subsequent generations will be relatively more effective than in the early genera-tions.

F1 and F2 seeds of four crosses were formed during 2001 and 2002 growing sea-sons. The F2 population’s plants were evaluated during 2003 growing season under the two planting dates (14th May and 29th June) to estimate the phenotypic correla-tion coefficients among eight plants characters and their contributions in the varia-tion of grain yield/ plant at the Agric. Res. Stat. of Fac. of Agric., Ain Shams Univ., Shalakan, Kalubia Governorate, Egypt. Results showed that grain yield/ plant under normal planting date correlated positively and significantly - in most cases - with each of ear diameter, ear length, number of kernels/ row, 100-kernel weight, number of rows/ ear, ear height, plant height and days to silking, while under late planting date, it correlated with each of number of kernels/ row, ear diameter, 100-kernel weight, ear length, number of rows/ ear, ear height and days to silking. Path coeffi-cient analysis estimates indicated that ear diameter; ear length and number of ker-nels/ row can be considered as the most important sources of plant grain yield varia-tion under normal planting date while, under late planting date they were number of kernels/ row, ear diameter, 100-kernel weight and ear length. It was concluded that each of ear diameter, ear length and ear length through its indirect effects via ear di-ameter are considered as the most important sources of plant grain yield variation.

Abiotic stresses represent a major impediment to crop productivity, especially in arid regions. Thus, over two years of 2014 and 2015, a field experiment was undertaken at El Nubaria region, Egypt to assess the productivity and water use efficiency (WUE) of sunflower as affected by planting dates (April 21, May 21, and June 21) and  irrigation levels (ET100%, ET85% and ET70%,). Results clarified that leaf chlorophyll a content was higher by sowing in May than in either April or June sowings, while leaf carotenoides of plant sown in May or June surpassed those sown in April. The minimal value of proline was obtained with sowing in May. Sowing in May increased plant height by 52.2 and 22.3 as well as LAI by 19.3 and 73.1% than sowing in April and June, respectively. The reductions in seed yield, oil yield and WUE amounted to 10.5 and 12.8, 13.7 and 18.3 as well as 11.8 and 9.8 % with April and June sowings, respectively, compared to May sowing. ET100% showed superiority over than ET85% and ET70% in improving sunflower yields and its attributes, but WUE did not affect. Sunflower sown in May and irrigated with ET100% gave the maximum values of seed yield and its attributes and WUE surpassing other interaction treatments. In June, WUE value increased under severe water deficit i.e. ET70% comparing to moderately water–stressed (ET85%) or well–watered conditions (ET100%).

The present investigation was carried out at the Experimental Farm of the Faculty of Agriculture at Fayoum, Cario University at Dalla, Fayoum Governorate during the two seasons 2000/2001 and 2001/2002. The aim of this investigation was to study the effect of organic manure and number of berseem cuts on cotton yield and its components and fiber traits. The obtained results indicate that only plant height at harvest, number of fruiting branches / plant and the height of the 1st fruiting branch were significantly affected by organic manure (O.M.) application. On the other hand, organic manure did not affect significantly the seed cotton yield, yield components and fiber quality traits. Cotton planting dates affected significantly all studied vegetative growth, seed cotton yield, yield components and fiber quality traits. Early planting date (1st week of March) showed significant superiority over the other two planting dates (1st week of April & May) in number of fruiting branches/ plant, number of days to 1st flower appearance and 1st boll opening, number and weight of open bolls/ plant in the 1st& 2nd pickings, seed cotton yield, lint percentages and studied fiber quality traits. The decreases in the total seed cotton yield attributed to the late planting dates (1st week of April & May) amounted 26.4 and 84.8% and 30.6 and 84.1% of  March planting with the treatments of 10 and 20 m3/ fad organic manure, respectively.

Two field trials were carried out at South Tahrir Research Station (Ali- Moubark). These trials were conducted in 2003 and 2004 to evaluate three planting dates of maize (the over story shade crop) intercropped with groundnut i.e, on 1st June, 10th June and 20th June, and four plant densities of maize intercropped with groundnut, i.e, maize was spaced at 50 and 100 cm apart leaving one or two plants/hill. Groundnut (the main crop) was grown on all rows. The data obtained indicate that ear length, ear diameter, number of rows/ear, number of kernels/row and the weight of 100grains increased with increasing maize spacing as well as with diminishing the number of plants remained per hill after thinning (to one plant/ hill). On other hand dense planting resulted in higher yield of maize whether by narrowing maize spacing or increasing the number of maize plants per hill after thinning. Yield and yield components of maize were significantly decreased by delaying planting date of maize up to the latest date. Yield /fed and yield components of groundnut were associated with maize density and distribution. The more the shade offered by maize the less the values of these traits were obtained. Highest values were obtained when maize was spaced at 100cm. and thinned to one plant/ hill. Increases in the values of yield and yield components of groundnut were associated with delaying the planting date of maize. Delaying the planting date of maize resulted in increases in the values of land equivalent ratio (LER) and the relative crowding coefficient. The treatment effect at any planting date of maize exerted very low competitive pressure when aggressivity was measured. With delaying seeding maize, competitive ratio (CR) diminished to the least. Spacing maize at 50cm. apart and leaving two plants / hill after thinning resulted in highest value of LER and relative crowding coefficient (RCC). Nor any maize density had any heavy competitive pressure on groundnut when aggressivity was measured