The present investigation was conducted using six flax genotypes with their 15 F2 crosses grown under two environments {normal soil (E1= Kafr El-Hamam-Shrkia Governorate) and saline soil (E2= Tag El-Ezz,-El Dakahlia Governorate)} to determine the combining ability and gene action of some agronomic flax characters in these entries (parents and their crosses). In 2009/10 season, the six parents { P1= Giza 8, P2 (S.402/1) , P3 (S.420/140/5/11), P4 (S.421/43/14/7), P5 (S.533/39/5/3) and P6 (Daniela)} as well as their 15 progenies were sown in first week of November to evaluated in a randomized complete block design with three replicates at the two above-mentioned locations. High ratio of GCA/SCA revealed that additive played greater role than nonadditive genetic effects in the inheritance of straw weight and its components as well as seed weight, 1000-seed weight and number of seeds/capsule under the two environments and combined analysis. On the other hand, both additive and nonadditive types of gene action were involved in the inheritance of number of capsules/plant. Mean squares of interaction between environment and both types of combining ability for most studied traits revealed that the magnitude of both additive and non-additive types of gene action varied from environment to another. Whereas the non-additive genetic effects are more influenced by saline environment than additive effects in each of straw weight, plant height, technical stem length, seed weight, 1000-seed weight and number of seeds per capsule. While, additive gene effects were much more influenced by saline environment than non-additive effects for number of capsules per plant. P5(S.533/39/5/3) exhibited good general combining ability effects for straw weight per plant and its two important components; plant height and technical stem length in addition P2 for both seed weight and 1000-seed weight as well as P1 for 1000-seed weight under the two environments and combined data. For Sij effects, one cross (P5P6) which exhibited positive significant SCA effects for straw weight per plant and its components as well as seed weight per plant and number of capsules per plant in addition three crosses (P1xP3, P1xP6 and P4xP6) for 1000-seed weight under the two environments and combined analysis. Therefore, these crosses are suitable in breeding program for increasing the previous characters. The correlation between cross means and their SCA values was significant and positive for straw weight and its components as well as seed yield and its two important components, number of capsules per plant and 1000-seed weight indicating that high performing crosses were high specific combinations.

No abstract

The materials used for the present study consisted of fourteen kenaf genotypes (G) which were evaluated over six environments (three at Ismailia Governorate, two at Giza Governorate and one at El-Beheira Governorate) through three successive seasons (2009 to 2011). in Egypt. The analysis of variance revealed highly significant differences among genotypes, environments and G x E interaction for all studied traits, indicating a wide range of variation among genotypes, environments and these genotypes exhibited differential response to environmental conditions. The significant variance due to residual for all characters indicated that genotypes differed with respect to their stability suggesting that prediction would be difficult, which means that mean performance alone would not be appropriate. Interaction component of variance (σ 2 ge) was less than the genotypic variance (σ 2 g) for all characters. This means that genotypes differ in their genetic potential for these traits. The observed narrow range between phenotypic and genotypic coefficients of variability with high heritability in broad since for fiber percentage. Also, fiber weight per plant, technical stem length and plant height showed similar results, indicating possibility of using these three yield traits in selection criteria with giving more weight for fiber weight per plant and technical stem length for improving green stalk yield per plant in turn fiber yield. The criterion, yield stability (YSi) statistic indicated that S.105/2 and S.113 were proved to be superior in yield and stability for all characters studied as well as three genotypes, S.96/20, Giza3 and S.8 were stable for most characters studied. Therefore, the two genotypes (S.105/2 and S.113) maintained mean performance advantage across nearly all the environments sampled by maintaining high level for the above-mentioned traits and they are recommended to be released as commercial stable high yielding cultivars and/or to be incorporated in kenaf breeding program for producing stable high yielding lines. Phenotypic correlation coefficients among green stalk weight with other related characters of kenaf, indicated that, plant height, technical stem length, and fiber percentage are the major components contributing to green stalk weight per plant. Therefore, selection for these traits will improve green stalk weight per plant and in turn fiber yield in kenaf.

Two field experiments were conducted at the experimental Farm of Etay El-Baroud, El-Beheira Governorate, Egypt. These trials included forty lines sown in F6 (in season, 2009/10) and F7 generation (in seasons, 2010/11). The objective of this investigation is to compare these lines through two generations with the two commercial varieties, Sakha 1 and Sakha 2 for straw, seed, oil yields and their related traits. These materials were evaluated in a randomized complete block design with three replications at the two previous seasons. Mean squares due to lines were significant for straw weight, seed weight and their components as well as for technological traits, fiber percentage and oil percentage in both seasons. Phenotypic (PCV) and genotypic (GCV) coefficient of variability and broad sense heritability (H%), the slight discrepancy between PCV and GCV for straw weight components (plant height, technical stem length and fiber percentage) and also for seed weight components (oil percentage and 1000-seed weight) were reflected in the high heritability estimates in both seasons for these traits, indicated the possibility of using these yield component traits in selection index technique to achieve further improvement both straw and seed weights by selection for these components. Concerning mean Performance, out of forty flax lines, five lines, (No. 18, 20, 34, 35, and No. 40) were superior for each seed, oil, straw and fiber yields/fed. Therefore, these five lines may be considered good substitutes for the low yielding ones, Sakha 1 and Sakha 2 in future after evaluation in more locations and years before releasing as a new Egyptian flax cultivar for both straw and seed yields production (as a dual purpose type). Straw weight per plant was significantly positively correlated with each of plant height, technical stem length, number of capsules per plant and 1000-seed weight in both seasons. Also, plant height exhibited positive correlation with technical stem length in both seasons, indicating that maximization of straw weight per plant may be obtained by selection for these component variables specially plant height and technical stem length. Seed weight per plant, exhibited positive association with oil percentage in both seasons. Whereas, number of capsules per plant was highly positive correlation with 1000-seed weight, indicating the possibility of selection for a genotype as dual purpose type which had high seed weight and high straw components (plant height and technical stem length).

Twenty-four flax genotypes {21 promising lines and 3 check varieties, Giza 8 (oil type), Sakha 1 (dual purpose type) and Sakha 3 (fiber type)} were evaluated for straw, seed, oil yields and their related traits under two different environments (Sakha Exp.Station, Kafr El-Sheikh Governorate "clay soil" and Ismailia Exp.Station, Ismailia Governorate "sandy soil") through two successive seasons, 2008/09 and 2009/10. These materials were evaluated in a randomized complete block design with three replications at the two above-mentioned locations. The collected data indicated that, Genotypes mean squares were highly significant for straw, seed, yields/fed and their related traits. The genotype x year variance ( 2 gy) was less than the genotype x location variance ( 2 gl) for all characters, except plant height and oil percentage. Consequently evaluation should probably stress using more locations but testing over a shorter period of times. Heritability values (H%.) in broad sense were high for plant height and two important components of seed weight (seed index and No. of capsules/plant). Also, the observation of narrow range between phenotypic (PCV) and genotypic (GCV) coefficients of variability, which gave almost similar values of PCV and GCV in plant height was mainly due to genetic differences as evidenced from the very high heritability. Also, straw weight per plant and long fiber percentage as well as the two important components of seed showed similar results, indicating possibility of using these yield components (seed index and No. of capsules per plant) in selection index for improving seed weight per plant as well as plant height to improve straw weight per plant. Concerning mean performance and susceptibility index as affected by environmental stress for sandy soil, line 541-C/3 exhibited high yielding potential with high tolerance for straw and fiber yields per fed, but this line exhibited moderate tolerance for both seed and oil yields per fed. Also, line 541-D/10 exhibited high yielding ability with moderate tolerance to sandy soil conditions for each of straw, fiber, seed, and oil yields per fed. Hence the two promising lines, 541-C/3 and 541-D/10 may be consider good substitutes for the low yielding ones, Giza 8, Sakha 1 and Sakha 3 in future after evaluation in more location before releasing as a new Egyptian flax cultivar and may be useful as potential breeding material for releasing cultivars to sandy soil conditions (suitable to grown in sandy soil) for fiber and oil "dual purpose".