Ricardo Montalván

Relationships among oil content, protein content and seed size in soybeans

During 1995/96 and 1996/97, experiments were carried out at Londrina State University, aiming at quantifying the oil and protein contents in two groups of soybean genotypes; estimating the phenotypic, genotypic and environmental correlations existent among oil, protein content and seed size, and identifying genotypes for direct human consumption with high protein content. The evaluated characters were Weight of a Hundred Seeds (WHS), expressed in grams/100 seeds, Oil Content (OC) and Protein Content (PC), expressed in %. In the experiment carried out in the field, OC ranged from 12 to 20.37 % and PC from 35.66 to 41.75% while in the experiment carried out in the greenhouse OC ranged from 12.26 to 21.79 % and PC from 32.95 to 41.56 % . The correlations between oil and protein were negative and significant. The relationship among WHS with OC and PC was low and higly affected by the time effect. Due to their high protein content and stability to oil and protein contents, there were distinction among the treatments carried out in the field (GA23 and GA20), and those carried out in the greenhouse (PI408251, Waseda, B6F4 (L-3 less), PI423909 and Tambagura).

Use of seed protein polymorphism for discrimination of improvement level and geographic origin of upland rice cultivars

Grain proteins from 58 Brazilian and nine Japanese upland rice cultivars (Oryza sativa L.) were electrophoretically separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Densitometric scanning of the electrophoretic profiles permitted the estimation of the relative concentration of 16 protein fractions, which were used as variables for the calculation of Fishers canonical discriminating functions. Significant differences between mean values of protein fractions were useful in distinguishing Brazilian and Japanese cultivars, as well as improved and non-improved Brazilian rice cultivars in scattered plots. Electrophoretically detectable protein polymorphism in rice grain can indicate geographic origin as well as breeding improvement level of a cultivar. Improved cultivars were those released by plant breeding institutes.

Genetic gain and correlations among traits for stink bug resistance in soybeans

An experiment was carried out at the State University of Londrina School Farm in a randomized complete blocks design with three replications; the plots underwent natural stink bug attacks to check correlations existing among agronomic traits and stink bug damage in 33 F8 pure lines soybean. The seed size trait was measured by the weight of a hundred seeds (WHS) and the percentage of stink bug damage seeds (PDS) was measured by staining the seeds with tetrazolium at 0.01%. Seeds were considered damaged with at least one puncture and or with marks characteristic of stink bug. The phenotypic and genotypic correlations between the WHS and the PDS seeds were positive, being 0.51 and 0.67 ± 0.19, respectively. The relationship between the visual pod width (VPW) and PDS was also significant, being 0.41 and 0.54 ± 0.19 for phenotypic and genotypic correlations, respectively. Thus the breeder can select lines for stink bug resistance indirectly either by WHS or VPW. These two traits are very easy to assess when compared with the assessment of PDS damage, allowing the use of larger populations. However, in this case, the genetic gains by selection were smaller than those obtained by direct selection, but even so they were considered noteworthy. The VPW may be an efficient way of selection in large populations for stink bug resistance.

Genealogia dos cultivares brasileiros de arroz-de-sequeiro

The several studies have shown that the genetic base of upland and irrigated Brazilian rice cultivars is narrow. It is recommended, therefore, to amplify it, reducing genetic vulnerability and increasing yield. In the present work, genealogies of Brazilian upland rice cultivars recommended for 1997/98 for natural and supplementary - irrigation conditions were elaborated, and genetic contribution of their ancestors was estimated. This information is very important in rice breeding programs in order to plan crossings.

Comparison between the SPD and the SPDS methods for segregating generation advancement in soybean

The purpose of this work was to compare the SPD (Single Pod Descent) and SPDS (Single Pod Descent with Selection) methods for segregating generation advancement in soybean breeding. Sixteen populations derived from crosses among Japanese and adapted Brazilian soybean were used. The traits, number of days to flowering (NDF) and to maturity (NDM), plant height at flowering (PHF) and at maturity (PHM), and individual plant yield (IPY) were assessed. The populations obtained by SPDS showed values close to the variation in the populations obtained by SPD. Regression through the origin showed that both methods were equivalent for NDM in the F3 generation and for NDF in the F4 generation. For all other trait/generation combinations, SPDS yielded superior means. Therefore, it was preferable to use SPDS because it allowed the advance of generations with smaller population size.