الفهرس 
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Abstract
This study was carried out at the Vegetable Research Department, Kaha Horticultural Experimental Station Barrage Horticultural Experimental Station and Plant Pathology Institute during the period of 2005-2010 to study the inheritance of resistance to powdery mildew Sphaerotheca fuliginea, vegetative growth (plant length- number of branches- number of leaves), Earliness, yield component (early yield- marketable yield -
total yield- average fruit weight), fruit characteristics (fruit length- fruit diameter – fruit shape index – fruit flesh thickness – total soluble solids) in comparison with the commercial hybrid (Galia) F1. Hazera company Six melon inbred lines namely, i.e 102 (p1) – 103 (p2) – 105 (p3) – 107 (p4) – 108 (p5) – 114 (p6) (Cornell University – Department of Plant Breeding), in addition to their fifteen F1hybrids were used in the study. The first experiment : In the summer and autumn seasons of 2005, the parental lines were selfed to secure enough seed and to increase the homogeneity degree. The six
inbred lines were evaluated under artificial inoculation by powdery mildew spores. The experiment was carried out in the greenhouse of plant. Pathology institute. A complete randomize block design system with there replicates was adopted. Each replicate contain 6 pots ( 30 cm in diameter) for all inbred lines. Seeds were sown on the 25 th of September 2006. three seeds were sown in each pot and on the 15th of December after being artificially inoculated by Sphaerotheca fuliginea spores suspension with (500.000 spores /ml). Plants at the four true leaf stage were artificially inoculated by using conidia on fresh leaves were dislodged with help of atomized water and collected in a cup, then they were transferred to a hand sprayer which was used to distribute them onto plants (Shosha et al.1987). In this experiment, data were taken for the degree of resistance of inbred lines under artificial inoculation. In the summer seasons of 2007 all possible combinations of half diallel crosses were made among the parental lines to generate the required F1seeds. In the summer seasons 2008 the 22 entire, viz, six parental lines, fifteen F1,s hybrids and Galia (control) were sown in field experiment that was designed to estimated the mean performance, general and specific combining ability effect, heterosis and heritability of some plant and fruit characters. A randomized complete block design with three replications was used. The second experiment : The object of this experiment was to study the inheritance of resistant to powdery mildew. In autumn 2008 seeds of six parental lines, their fifteen hybrids and Galia commercial F1hybrid (control) were planted in plastic house in Plant Pathology Institute at Giza with A randomize complete block design with three replication was conducted. Plants were inoculated at the three leaves stage. Inoculation with the casual fungus was made as previously described in the first experiment. 3-4- Recording data : 3-4-1-Vegetative growth : 3-4-1-1-plant length (cm) - 3-4-1-2-Number of branches /plant - 3-4-1-3- Number of leaves /plant on the main stem - The vegetative growth data were recorded at the beginning of the Earliness stage. 3-4-2-Earliness : 3-4-2-1- The number of days from planting till 25% the first hermaphroditic flower on thesis of experimental unit. 3-4-3- Yield component : 3-4-3-1-Early yield (ton / Fed). It was calculated for the first tow harvests by weight .3-4-3-2-Marketable yield (ton / Fed).This included weight of all fruits free from diseases and disorders. 3-4-3-3- Total yield (ton / Fed). It was calculated as total weight of all harvested fruits through out the entire season. 3-4-4- Fruit characteristics : 3-4-4-1-Average fruit weight (gm) - 3-4-4-2- Average fruit length (L)(cm) - 3-4-4-3- Average fruit diameter (D) (cm) - 3-4-4-4-Fruit shape index (L/D) - 3-4-4-5- Fruit flesh thickness (cm) - 3-4-4-6- Total soluble solids (T.S.S) %. It was determined using a hand refractometer according to Welles and Buitelaar(1988). The obtained results could be summarized as follows :- 1- The results indicated significant differences among different parental genotypes and hybrids concerning all studied characters. Except fruit diameter, was no significant among parental lines .2- significant heterosis values relative to mid parent were detected for all studied traits. 3- The results showed significant general and specific combining ability effects which indicate the presence of both additive and non- additive gene effects in the inheritance of all characters. 4- The ratios of GCA/ SCA variances were greater than unity for number
of branches/ plant, leaves/ plant, number of days from planting to first Earliness, flesh thickness, early yield, marketable yield, total yield and total soluble solids and the inheritance of resistance to powdery mildew.Indicating that the inheritance of these traits were mainly controlled by additive gene effects. However ratios were less than unity for plant length, average fruit weight , fruit length, fruit diameter and fruit shape
index, indicating importance of non- additive gene effects.5- The broad sense and arrow sense heritability estimated for all studied traits. Combining ability : 6- The parental 102 was a good combiner in forming hybrids with plant length, number of branches/ plant, number of leaves/ plant, average fruit weight, fruit length, fruit shape index and the inheritance of resistance to powdery mildew.7-The parental 103 proved to be good general combiner for average fruit weight.8-The parental 105 was found to be a good combiner in forming hybridswith number of days from planting to first Earliness, early yield,marketable yield, total yield and the inheritance of resistance to powdery mildew. 9- The parental 107 was a good combiner in forming hybrids with early yield, total yield, marketable yield and total soluble solids.10- The parent 108 was found to be a good combiner in forming hybrids with fruit shape index.11- The parent 114 was found to be a good combiner in forming hybrids with plant length , number of branches/plant, number of leaves/ plant, early yield, marketable yield, total yield, average fruit weight, total soluble solids and the inheritance of resistance to powdery mildew. 12- Evaluation of specific combining ability effect of different hybrids for investigated traits indicated that some of F1 combinations were characterized by high specific combining ability effects and involving at least one parent as good general combiner and there fore could be useful for varieties improvement purposes in terms of the probability of isolating
desirable transgressive segregates for these characters. Heritability : 13- the broad and narrow sense heritability estimates for plant length (98.72-51.54 %), number of branches (74.39- 45.29 %), number of days from planting to first Earliness (68.27- 60.40 %), marketable yield 61.24 - 48.93 %), average fruit weight (40.71-72.37 %) and total soluble solids (5.07 –99.70 %) respectively which indicates that these characters can be
improved through individual plant selection in segregation gene.14-The broad and narrow sense heritability estimates for fruit shape index fruit diameter,fruit length, total yield ,number of leaves/plant,early yield and fruit flesh thickness were (36.54- 17.89 %), (25.22- 21.13%), (43.82 – 11.74 %), (63.59- 49.09 %), (66.58- 30.18 %), 68.13- 31.01%) and (83.24- 43.88 %) respectively. These results indicate the influence of the
environmental factors and non- additive type of gene action on the expression and inheritance of these characters. Selection in the segregation generation to improve these characters should be performed on family mean basis. Heterosis : 15-The F1hybrid 105x 114 (p3 x p6) scored the highest values mid parent heterosis for plant length 31.87 %, number of leaves/plant 24.8 %, early yield 160.27 %, marketable yield 168.58 %, total yield171.52 % and T.S.S 56.19 %. 16- The F1 hybrid 102x 108 recorded the highest values mid parent heterosis for fruit length 59.75 % and fruit shape index 48.95 %. 17- The F1 hybrid 102x103 recorded the highest value mid parent heterosis for fruit flesh thickness 25 %. 18- The F1 hybrid 102x114 scored the highest value mid parent heterosis for number of branches 57.21 %. 19- The F1 hybrid 105x 108 showed the lowest value mid parent heterosis for number of days from planting to first Earliness -1.38 %.20- The F1 hybrid 103x 114 showed the highest value mid parent heterosis of fruit diameter 13.65 %.