The aim of the study was to verify whether a mixture of lines containing equal amounts of seven lines of Carioca-type common bean, all agronomically uniform but each presenting different patterns of resistance to Colletotrichum lindemuthianum, would be less damaged by anthracnose than the individual pure lines. Plants cultured in experimental plots in Lavras, Minas Gerais, Brazil, in the dry harvest seasons of 2007 and 2008 were inoculated with a mixture of races 65, 81, 87, 89 and 337 of the pathogen, and the severity of anthracnose was evaluated at 10-day intervals commencing 12 days after inoculation. The progress of the disease was estimated from the coefficients of the linear regression equations (b 1 ) and from the areas under the disease progress curves (AUDPC). The mean grain yields were determined in both experimental periods. The value of b 1 for the multiline was not different from that presented by the resistant line MA-II-22 and indicated a slower progress of the disease over time compared with susceptible lines. There were no differences in AUDPC values between the multiline and the resistant lines. The multiline presented a grain yield that was similar to those of the most productive lines even though susceptible lines comprised more than 28% of the mixture and such lines showed the lowest yields of grain. It is concluded that the use of the mixture of lines represents a good strategy for reducing the progress of anthracnose in the field and, as a consequence, reducing loss of grain yield.

World’s ornamental plant market, including domestic market of several countries and its exports, is currently evaluated in 107 billion dollars yearly. Such estimate highlights the importance of the sector in the economy of the countries, as well as its important social role, as it represents one of the main activities, which contributes to income and employment. Therefore a well-structured plant breeding program, which is connected with consumers’ demands, is required in order to fulfill these market needs globally. Activities related to pre-breeding, conventional breeding, and breeding by biotechnological techniques constitute the basis for the successful development of new ornamental plant cultivars. Techniques that involve tissue culture, protoplast fusion and genetic engineering greatly aid conventional breeding (germplasm introduction, plant selection and hybridization), aiming the obtention of superior genotypes. Therefore it makes evident, in the literature, the successful employment of genetic breeding, since it aims to develop plants with commercial value that are also competitive with the ones available in the market.

The aim of this study was to compare transgenic and conventional soybean cultivars in regard to yield performance and agronomic traits. Six soybean cultivars were tested: three conventional cultivars and their three isogenic transgenic derivatives, in two locations, Lavras and Patos de Minas in Minas Gerais, Brazil, in the 2012/13 crop season. Data on yield (kg•ha −1), plant height (cm), and tolerance to lodging were collected. The cultivars had different responses. The cultivar BRS/MG46 Conquista had lower yields than its isogenic derivative BRS Valiosa RR, but this was not seen with the conventional cultivar M-SOY 6101, which produced more than its isogenic derivative M-SOY 7211 RR. Between the isogenic cultivars BRS/MG68 Vencedora and BRS Favorita RR, there were no significant differences. Nevertheless, the contrast between the mean values of the transgenic and conventional cultivars shows that the conventional cultivars had mean values greater than the transgenic cultivars.

The current study aims to measure the effect of pre-sowing desiccation period and verify the influence of post-emergence herbicide on soybean agronomic traits and grain yield. The experiments were carried out according to a randomized complete block design with three replications during two crop seasons (2012/13 and 2013/14), using split plot design. Five soybean cultivars were used (BRS Favorita RR ® , TMG 1179 RR ® , TMG 1176 RR ® , Anta 82 RR ® , NS 7100 RR ®). Two desiccation periods were adopted 7 days before sowing and just before sowing. Two types of weed management were tested in postemergence-using glyphosate (Roundup Ready ®) and a soybean selective herbicide (Robust ®). During the 2013/2014 crop season, manual weeding was also used. The evaluated traits were plant height, first pod insertion, number of pods per plant and number of seeds per pod, 1,000-grain weight and grain yield. Considering the distinct post-emergence herbicides, there was no significant difference between glyphosate and Robust ®. Nevertheless, the desiccation period showed significant differences in plant height, number of pods per plant and grain yield. The soybean grain yield was higher when desiccation was done 7 days before sowing. Therefore, an association between desiccation period and soybean performance was assumed.

ABSTRACT. Currently, one of the acclaimed alternatives for increasing maize yield is accomplished through utilization of heterosis in hybrid cultivars. However, upon performing crosses between related pairs, there are losses due to inbreeding depression. Thus, the aim of this study was to estimate inbreeding depression and the contribution of loci in heterozygosity in different types of maize hybrids. Eight treatments were evaluated, considering the F 1 and S 0 generations of four commercial hybrids. A randomized block experimental design was used, with three replications, and plots consisting of two three-meter long rows at a spacing of 0.50 m. The traits evaluated were plant height, first ear height and husked ear weight. For ear weight trait, there was a significant difference, where the treatments could be classified into three distinct groups. In this case, the single-cross hybrids AG7088 2 F.B.S. Botelho et al. Genetics and Molecular Research 15 (3): gmr.15035497 and 30F90Y exhibited greater depression through inbreeding due to the greater contribution of loci in heterozygosity and consequent predominance of deviations due to dominance.