No abstract

A major obstacle in corn (Zea mays L.) breeding programs is how to obtain strains which, when combined, ensure increased productivity in all crop characteristics. Therefore, the objective of this study was to evaluate the prediction efficiency of hybrid maize using diallel analysis and the best linear unbiased predictor (BLUP). Eight synthetic varieties were sown in a diallel scheme and the hybrid and their parents were then evaluated in three separate environments; both combining ability and predicted breeding values (BLUPs) were estimated. Correlations between the BLUP and combining abilities were also obtained. Combining ability analysis revealed that both additive and non-additive types of gene action were important in the studied traits. There was a moderate to high correlation between the mean square of the combining ability and the predicted breeding values. This shows that BLUP can be used to select the best parents for different traits, especially for ear height and ear position, which had the highest correlations. The parent VAR-01 had significant general combining ability (GCA) values, and it can be used in crosses to reduce plant height, ear height, and ear position while the parent VAR-06 can participate in crosses to increase ear height, plant height, and ear position. The result obtained for combining ability was moderately to highly consistent with BLUP results, but selection must be carefully undertaken.

The Brazilian popcorn has low genetic variability and the successful development of advanced lines, new popcorn cultivars with high grain yield (GY) and expansion volume (PE) is dependent on parental selection and precise determination of heterotic groups. The aim of this study was to evaluate genetic variability and identify heterotic groups in synthetic populations of popcorn, using diallel crosses. Thus, nine synthetic populations were crossed using complete diallel scheme. The GY and PE traits of 36 hybrids and reciprocals were evaluated in a randomized complete block design with 72 treatments and two replicates in two years. The effects of non-additive genes were the most important in the genetic control of these traits, indicating a favorable situation to produce hybrids. The reciprocal effect is mainly due to non-maternal effects for GY and PE. The highest GY values were obtained for the 02 x 08, 04 x 09, 05 x 09, and 01 x 09 crosses and the highest PE were obtained for the 07 x 01 and 03 x 04 crosses. The exploitation of synthetic populations from S3 lines can be an alternative to increase the genetic variability for grain yield and popping expansion in popcorn breeding programs.

Biofortification is a process in which plant species are improved in order to raise the nutritional content of the product consumed. The following are some of the main techniques that can be introduced in plant breeding programs in order to improve the nutritional quality of the food to be produced. The rice breeding for higher Fe and Zn content in grain, rice breeding for higher β-carotene content in the grain, rice breeding for higher folate content in the grain, techniques used for plant transformation, transformation via protoplasts, transformation via bioballistics (or biolistic), transformation via Agrobacterium tumefaciens, identification and in vitro selection of transformed tissues, concepts of gene expression and regulation, protein expression, proteomics, mutant study, patch-clamp, were studied. It is necessary to verify the occurrence of variability among the rice genotypes for the Fe, Zn and B complex vitamins; therefore, it will be possible to select these materials within breeding programs. The simple selection of these superior genotypes in relation to nutritional quality, even though by means of conventional breeding techniques, can bring benefits to rice consumption by the human population.

The objective of the present study is the evaluation of genetic parameters in F 4 and F 5 soybean populations from two crosses, which are potentially resistant to Asian soybean rust. The genotypes were developed from the cross between parents, which were resistant and susceptible to the disease, and totaled 137 genotypes in generation F 4 and 283 genotypes in F 5. The experimental design was augmented blocks with two checks between the treatments. The following agronomic characters were evaluated: plant height at maturity, first pod insertion height, number of nodes and branches, agronomic value, lodging, number of pods and seeds per plant and seed production. After the genotypes were submitted to analyses of variance, heritability, and selection gains, it was observed that Cross 1 had superior progenies, which were potentially resistant to Asian soybean rust and also had good productivity.