In order to evaluate molecular and phenotypic diversity and detecting molecular markers for six summer squash inbred lines belong to species [Cucurbita pepo L.], five RAPD and five ISSR primers were used as well as 12 economical traits were estimated. These primers succeeded in generating reproducible and reliable amplicons. RAPD revealed 88.1 % of polymorphism while ISSR techniques showed 80.5% polymorphism. The resolving power (Rp) value for RAPD technique was 5.00 which was higher than 3.40 of ISSR technique. Therefore, the RAPD technique was better than ISSR technique in evaluated molecular diversity and discrimination capacity among lines. But, the ISSR technique was better than RAPD technique in showing unique markers (21 for ISSRs and 9 for RAPDs). Also, the correlation between phenotypic distance (PD) and molecular distance (MD) based on ISSRs was 0.173 highest than with MD based on RAPDs (0.045). On the other hand, with the exception of P6 which gave significant desirable value in two traits (number of fruits and yield per plant), each of the other five strains gave a significant desirable value in one trait, thus the number of these traits which distinguished in the six inbred lines were 7 traits. These traits could be linked with all unique markers detected in this study. The inbred line P5 showed the highest number of unique markers (10, 9 of them were positive), one or some of which may be linked with NL trait that showed in this inbred line a significant desirable value. Followed by the inbred line P6 which showed seven unique markers (six of them were positive) one or some of which may be linked with NF and/or Y/P traits. This indicated that some of these markers may be used as markers assisting selection in the breeding and improvement of squash.

No abstract

Genetic development of improved genotypes with good floral charactaristics is the an important approach in the production of hybrid rice seed. Ten rice parental lines where four of them have cytoplasmic male sterility while the other six use restorer. These ling were crossed to obtain 24 hybrid combinations, through a factorial mating design. The parental lines and their 24 F 1 hybrids were grown in randomized complete blocks design with three replications at Rice Research and Training Center Farm, Sakha Kafr El-Sheikh, Egypt during the two seasons of 2011 and 2012. Data were recorded on six floral traits viz., anther length, anther breadth, number of pollen grains anther -1 , stigma length, stigma breadth and glume opening angle. The analysis of variance of all genotypes revealed highly significant mean squares for all studied traits, suggesting the presence of genetic differences among the genotypes used in this study. The magnitude of genetic parameters indicated that the additive variance (σ 2 A) for anther length, number of pollen grains anther -1 , glume opening angle traits were higher than the corresponding nonadditive variance including dominant (σ 2 D). These results indicated that these traits were largely governed by additive gene action. Thus, the estimated values of heritability in broad sense were higher than heritability in narrow sense for all the studied floral traits. A major part of the total phenotypic variance was due to non-additive including dominance genetic variances for all floral traits. The maternal effects were affective in stigma breadth (37.25%) and glume opening angle (70.15%). The contribution of maternal and paternal interactions (Line x Tester) were found to be vital for anther breadth (57.86%) and stigma breadth (37.43%). The ten parental lines were distinctly classified into two major clusters (below 1200 Euclidean distance) according to the similarity diagram.

Six yellow inbred lines of maize, were setup in a half diallel crosses mating design, to produce 15 F1 hybrids. All genotypes with the three commercial checks : SC 155, SC 162 and SC 170 were evaluated using the two nitrogen levels : 80 and 120 kg N/fed during the 2007 growing season at Sakha Agriculture Research station Kafr El-Sheikh. The aim of this study was to estimate the phenotypic and genotypic correlations, GCA, SCA and their interactions with the two nitrogen levels. The results would also identify the superior genotypes for yielding performances. The studied traits were : grain yield (Ard./fed)., ear length (cm), ear diameter (cm), number of rows / ear and weight of 100 kernels(g).The results indicated the presence of significant differences among genotypes for most studied traits .This finding was expected due to the different origin of the parental inbred lines.General combining ability (GCA) and specific combining ability (SCA) mean squares were significant or highly significant for most studied traits under both nitrogen levels. The interactions between GCA and SCA with nitrogen levels were not significant for all studied traits except for SCA x N which was significant for weight of 100 kernels(g).The values of SCA mean squares were higher than those of GCA mean squares for grain yield (Ard./fed.), No. of rows / ear and weight of 100 kernels(g) traits. All means were higher under the high nitrogen level than the low nitrogen level for all studied traits.The best general combiners for grain yield (Ard./fed.) were the inbred lines: Sk 5001/50 and Sk 7070/62.The single hybrids Sk5001/50 x Sk 5005/ 12, Sk 5002/9 x Sk 5005/16, Sk 5001/50 x Sk5005/16 and Sk 5002/9 x Sk 5001/5 showed positive significant SCA under the two nitrogen levels for grain yield Ard./fed.The phenotypic and genotypic correlations among the five studied traits were positive for all studied traits.

The present investigation was conducted to study the combining ability through L x T design of experiment hybrids for agronomic and yield and its component traits under normal and saline soil conditions. Six CMS lines were crossed with seven restorer lines to produce 42 hybrids where they along with their parental lines were evaluated. The analysis of variance for combining ability revealed highly significant differences among CMS and restorer lines for all agronomic and yield and its studied characters except for grain yield (ton/fed) under both normal and saline soil conditions. Among the CMS lines; Pusa 6A and IR69625A while among the restorers, PR3 and Giza 178R are proved to be good combiners for the majority of the characters including yield, by exhibiting values for high GCA effects. Out of 42 hybrid rice combinations, the top five hybrids based on SCA effects for grain yield characters under saline soil conditions are IR68902A/Giza 182R, IR70368A/Giza 178R, IR69625A/PR2, Pusa 3A/GZ6296R and IR58025A/PR2.

The present investigation aimed to study the genetic diversity among some genotypes of rice in two rice successive seasons 2014 and 2015 at the experimental farm of Sakha research station. Thus, genotypic coefficient of variance (GCV), phenotypic coefficient of variance (PCV), heritability in broad sense (h 2 ) and genetic advance (GA) were determined for all the studied traits. In addition, the nature and magnitude of genetic divergence estimated in 24 rice genotypes using Mahalanobis D 2 -statistics by considering 17 quantitative traits. High estimates of GCV and PCV were recorded for panicle excretion%, gelatinization temperature, grain elongation% and amylose content%. Heritability in broad sense was high for all characters under study. High heritability coupled with high genetic advance were recorded for number of filled grains/panicle and plant height traits. Based on genetic distance, the 24 studied genotypes were grouped into 11 clusters. Cluster III was the largest and consisted of five genotypes, followed by cluster X with four genotypes, while clusters VI and XI contained two genotypes for each one. However, clusters I, V, VII, VIII and IX included one genotypes for each one. The highest inter clusters distance (102.605) was between cluster V and XI while, the lowest one was found between cluster II and X (22.017). Principal component analysis revealed that seven quantitative traits (grain length, grain shape, plant height, amylose content%, 1000-grain weight, number of panicles/plant and panicle length) were significantly influenced the variation in these genotypes. Therefore, the present investigation determined the genetic variability in some genotypes that could be used to improve the rice breeding programme with respect studied traits.

No abstract

Forty two rice hybrids were produced using six CMS lines and seven restorers following line x tester mating design. This study aimed to find out to the best hybrid combinations in respect of their superiority over the best inbred check variety, for agronomic and yield traits under normal and saline soil conditions.Hybrids with a yield advantage over the highest yielding check variety or over the hybrid check variety were considered as promising. Among 42 hybrid rice combinations evaluated ten under normal soil conditions and eight under saline soil conditions were most promising with mean performance of grain yield ranging from 5.60 ton/fed. for 58025A/GZ5121R to 6.18 ton/fed. for IR69625A/Giza 178R (EHR1) under normal soil condition. Mean performance of grain yield of best promising hybrids under saline condition ranging from 3.22 ton/fed. for IR69625A/PR1 to 3.34 ton/fed. for IR69625A/GZ5121R. The yield advantage over best local check variety was ranged from 1.10 ton/fed. to 1.68 ton/fed. under normal soil condition and ranged from 0.28 ton/fed. to 0.40 ton/fed. under saline soil conditions. Standard heterosis (SH%) or superiority % estimates ranged from 24.44 to 37.33% under normal soil condition and ranged from 9.52 to 13.60% under saline condition for above mentioned hybrids. The hybrid rice combination IR69625A/GZ5121R recorded the highest yield over the best hybrid check variety EHR1 under saline soil conditions. * Measure of soil saturation. ** Measure of soil water extract 1:5.