In Hungary, we examined eight features of twelve direct cross hybrids over a period of three years. The twelve hybrids were derived from direct and reciprocal crosses of four parental lines. We did not find significant differences in the cases of stalk diameter and leaf number in the average of 3 years in any of the hybrids. Statistically expla...inable differences in primary branches were observed in hybrids UDH5 and UDH8 and also in UDH6 and UDH11. It was evident in both instances that degrees of heterosis in reciprocal crosses far exceeded those of direct ones. High tassel branch number was dominant over the low one; consequently, parents with higher tassel numbers enforced their effects during the formation of this trait in hybrids. We experienced positive correlation (r=0.67**) between plant height and main ear height. A positive correlation (r=0.89**) was also found between the tassel length of the main axis above the lowest and the upper side branch. We observed a medium correlation (r=-0.42**) between the number of primary lateral branches and plant height. The number of primary lateral branches showed the highest heterosis. These results can be utilized in practical selection and seed production.
Knowledge of genetic diversity among available parental lines is fundamental for successful hybrid maize breeding. The aims of this study were to estimate (1) genetic similarity (GS) and genetic distance (GD) (based on Jaccard index) in four maize inbreed lines; (2) to classify the lines according to their GD and GS; (3) to determine hybrid per...formance based on GD and heterosis for yield ability in 4x4 full diallel system. We used morphological description and AFLP (amplified fragment length polymorphisms) for estimation genetic polymorphism in four maize inbred lines. We estimated the applicability of genetic similarity in SC and reciproc hybrids for prediction of their performance.
Three primer combinations were used to obtain AFLP markers, producing 207 bands, 70 of whit were polimorphic. The dendogram based on genetic similarities (GS) and genetic distance (GD) and morphological description separated four inbred lines into well-defined groups. Morphological description just with AFLP analysis showed reliable results. In view of genetic distance, the UDL 1 line and their linear and reciprocal crosses showed significant heterosis effect, which was confirmed by heterosis calculation based on grain yield.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Authors estimated the genetic parameters and genotype effects of average daily gain (ADG), age (AGE) and lean meat percentage (LMP) using the field test data of Pietrain (Pi), Duroc (Du), Hampshire (Ha) pigs and their crosses. Data was collected by the Agricultural Agency of Administration between 1998 and 2010 originating from 68 herds. Datasets of the different crossing combinations (Pi, Du, Pi × Du; Pi, Ha Pi × Ha) were evaluated separately using bivariate animal models. The estimated heritabilities were moderately low: 0.24–0.29, 0.22–0.26 and 0.18–0.19 for average daily gain (ADG), age (AGE) and lean meat percentage (LMP), respectively. The estimated genetic correlation coefficients were negligible: -0.07–0.01 (ADG-LMP), -0.01–0.04 (AGE-LMP). The Pi × Ha and Pi × Du crosses showed 6.76% and 4.96%; 6.74% and 4,17% and 0.08% and 0.44% heterosis for ADG, AGE and LMP, respectively. Among the environmental factors the herd effects were substantial: 41.17%, 53.67% and 14.16% for AGD, AGE and LMP, respectively. The smallest environmental influences were found for LMP.
Heterosis breeding in maize caused gene erosion by using uniform inbred lines. In order to strengthen the genetic base, we established a gene bank containing lines with broad genetic variability, resistance and adaptability. The maize gene bank is a result of our work in the past two decades.
The gene bank originated from treatments of maize
Plant and ear height are very important characters not only for describing new varieties of maize (Zea mays L.), but for green and dry matter production, and even for grain yield. Significant positive correlations have been reported by various authors between plant height and stover yield, plant height and dry matter yield, and plant height and... grain yield. The height of the main ear is also correlated to plant height. It depends on the variety or the environment, but is likely to be the same height within a population. Many environmental and agronomical factors (e.g. plant density, fertilization, pests and diseases) influence the expression of these characters, which are not quality traits. Their expression is controlled by many genes and by the interactions between these genes. The heritability of these traits is high and they show significant genotypic variability and positive heterosis, as reported in many research publications.
Two field experiments were carried out during the 2014 and 2015 seasons to evaluate certain genotypes of Egyptian cotton under well irrigated and water stress conditions. The cross combination Giza 69 x Australy recorded the best values for better parent heterosis for all physiological measurements and earliness index under well irrigated a...nd deficit conditions. Of the female parents, Giza 86 was found to be a good general combiner for most yield characters under both normal and stress conditions, followed by Giza 94. Data illustrated that Giza 45 was the best general combiner for most fiber quality traits under both conditions. The cross combinations Giza 86 x Dandra and Giza 69 x Pima S6 showed significant positive SCA values for seed cotton and lint yield/plant under well irrigated and water deficit conditions. However, the combinations Giza 77 x PimaS6 and Giza 94 x 10229 recorded significant positive SCA effects for seed cotton yield/plant under stress. Whilst, the cross Giza 68 x 10229 recorded significant desirable SCA effects for most fiber quality properties. In this context, the estimates significant positive general and specific combining ability effects indicated that the epistasis and/or dominance effects for F1 hybrid in cotton could be important to a certain extent.
Grain number per spike was studed in 6 winter wheat varieties and all their 30 direct and reciprocal F1 hybrids. Parents
included 4 released Romanian variety, the old american Atlas 66 and a dwarf breeding line, Oradea 79. This line has a low number of
grains/spike, but is important in breeding program for here reduced height. General and
genetic effects were estimated using Griffing’s method 1, model 1, as modified by Cabulea (1983).
For this diallel crosses, gene interactions and the interaction between cytoplasm and nuclear genes were highly significant and
the ratio of additive and non-additive effects was close to one.
The variety Fundulea 29 showed the highest general combining ability and it is recommended as a good parent for increasing
grain number/spike. Mid-parent heterosis was significant in 9 out of the 30 cases, mostly in hybrids involving the breeding line Oradea 79.
In 3 cases the number of grains/spike of F1 hybrids was significantly lower than the average of the parents. The breeding line Oradea 79 had
a significant negative general combining ability, but showed significant positive specific combining ability in most crosses, as well as a
significant positive effect of its cytoplasm. These results are considered to indicate that there are chances of improving the grain
number/spike in some crosses with Oradea 79.