Scielo RSS <![CDATA[Crop Breeding and Applied Biotechnology]]> vol. 16 num. 3 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Diallel analysis in cowpea aiming at selection for extra-earliness]]> Abstract In Brazil, the production of cowpea is concentrated in the Northeast and North; however, in recent years, its cultivation has expanded to the Cerrado biome of the Brazilian Midwest region, where it is incorporated into production arrangements in the form of off-season. In this work, it was carried out a study on the extra-earliness in cowpea in order to select parents and crosses with cycle shorter than 60 days. A test with an F2 generation of a complete diallel cross involving five parents and ten crosses was carried out in a complete randomized block design with six replications. The parents IT82D-889 and AU94-MOB-816 stood out for extra-earliness flowering, while IT82D-60 and IT82D-889 stood out for extra-earliness maturity. The crosses IT82D-60 x AU94-MOB-816 and IT82D-60 x IT82D-889 were more promising in extra-earliness flowering, while IT82D-60 x IT82D-889 and IT82D-60 x MNC04-789B-119-2-3-1 were more promising for extra-earliness maturity. <![CDATA[Characterization and selection of interspecific hybrids of <strong> <em>Brachiaria decumbens</em></strong> for seed production in Campo Grande - MS]]> Abstract The breeding program Brachiaria developed by Embrapa Beef Cattle provides studies to obtain forage with agronomic characters desired by farmers. In this regard, in 2013 and 2014, a study was carried out in order to select the best Brachiaria decumbens intraspecific hybrids, which are superior in relation to production, forage nutritional value, and resistance to spittlebugs. Estimates of genetic parameters and gains with selection were carried out. It was found that there was significant variability between genotypes for all characters. Gain with selection (GS%) ranged from 12 to 324%, and the highest percentage was found for weight of pure seeds (PS) of seed collectors of the second harvest. For reproductive tillers (RT), C001 and R091 hybrids had better performance than the control, and this character may be considered as a parameter to estimate production of pure seeds before flowering starts. <![CDATA[Evaluation of SRAP markers for mapping of <strong><em>Pisum sativum</em></strong> L.]]> Abstract Linkage maps have become important tools for genetic studies. With the aim of evaluating the SRAP (sequence-related amplified polymorphism) technique for linkage mapping in Pisum sativum L., a F2 mapping population derived from an initial cross between cvs. DDR11 and Zav25 were generated. A total of 25 SRAP primer combinations were evaluated in 45 F2 plants and both parental lines, generating 208 polymorphic bands/markers. The markers were analyzed by the chi-square goodness-of-fit test to check the expected Mendelian segregation ratio. The resulting linkage map consists of 112 genetic markers distributed in 7 linkage groups (LGs), covering a total of 528.8 cM. The length of the LGs ranged from 47.6 to 144.3 cM (mean 75.54 cM), with 9 to 34 markers. The linkage map developed in this study indicates that the SRAP marker system could be applied to mapping studies of pea. <![CDATA[Genetic diversity and apple leaf spot disease resistance characterization assessed by SSR markers]]> Abstract Among the cultivation problems of apple production in Brazil, Apple Leaf Spot (ALS) disease represents one of the main breeding challenges. This study aims at analyzing the genetic diversity among 152 apple scion accessions available at the Apple Gene Bank of EPAGRI, located in Caçador, Santa Catarina/Brazil. Eleven genomic SSR loci were analyzed to assess genetic diversity of ALS resistant and susceptible accessions. Results revealed high genetic diversity of the studied accessions, being 120 exclusive alleles (67 unique) from scion accessions resistant to ALS, and a mean PIC of 0.823. The locus Probability of Identity (I) ranged from 0.017 to 0.089. The combined I was 4.11 x 10-16, and the Power of Exclusion was 99.99999259%. In addition, the DNA fingerprint patterns will contribute as additional descriptors to select parental for crosses and early identification of apple accessions for breeding purposes, and also for cultivar protection. <![CDATA[Environmental effect on sunflower oil quality]]> Abstract Sunflower is one of the most important oilseed crops and produces a high-quality edible oil. Balance of fatty acids in standard sunflower oil shows preponderance of linoleic rather than oleic acid, and conditions during seed development, such as temperature, changes the oleic/linoleic ratio of the oil. This work aimed to evaluate the environmental effect on fatty acid profile in a group of standard and high oleic varieties and hybrids. Seeds were produced during regular season crop and during off-season crop featuring different temperatures from anthesis to maturity. Fatty-acid composition was determined by gas chromatography. Levels of oleic acid, in standard oil genotypes, raised as the crop developed in warmer environment while levels of linoleic acid decreased, and the opposite was observed when the crop was grown under lower temperature. High oleic genotypes were less sensitive to environment switching and showed lower variation on fatty-acid composition. <![CDATA[Genetic engineering of cotton with a novel <strong><em>cry2AX1</em></strong> gene to impart insect resistance against <strong><em>Helicoverpa armigera</em></strong>]]> Abstract Embryogenic calli of cotton (Coker310) were cocultivated with the Agrobacterium tumefaciens strain LBA4404 harbouring the codon-optimised, chimeric cry2AX1 gene consisting of sequences from cry2Aa and cry2Ac genes isolated from Indian strains of Bacillus thuringiensis. Forty-eight putative transgenic plants were regenerated, and PCR analysis of these plants revealed the presence of the cry2AX1 gene in 40 plants. Southern blot hybridisation analysis of selected transgenic plants confirmed stable T-DNA integration in the genome of transformed plants. The level of Cry2AX1 protein expression in PCR positive plants ranged from 4.9 to 187.5 ng g-1 of fresh tissue. A transgenic cotton event, TP31, expressing the cry2AX1 gene showed insecticidal activity of 56.66 per cent mortality against Helicoverpa armigera in detached leaf disc bioassay. These results indicate that the chimeric cry2AX1 gene expressed in transgenic cotton has insecticidal activity against H. armigera. <![CDATA[RNAi-mediated resistance to SMV and BYMV in transgenic tobacco]]> Abstract Soybean mosaic virus (SMV) and bean yellow mosaic virus (BYMV) are two typical types of viruses that cause mosaic in soybean plants. Multiple viral infections at the same site can lead to 66% to 80% yield reduction. We have aimed to improve SMV and BYMV resistance in Vietnamese soybeans using gene transfer techniques under the mechanism of RNAi. In this study, we present newly generated transgenic tobacco plants carrying RNAi [CPi (SMV-BYMV)] resistance to the two types of viruses; 73.08% of transgenic tobacco lines proved to be fully resistant to SMV and BYMV. In addition, the number of virus copies in transgenic tobacco plants was reduced on average by more than 51% compared to the control plants (wild type). This promising result shows the potential of transerring the CPi (SMV-BYMV) structure in soybean to increase resistance of soybean to SMV and BYMV and advance the aims of antiviral soybean breeding in Vietnam. <![CDATA[Genetic and cytological diversity in cherry tree accessions ( <strong><em>Eugenia involucrata</em></strong> DC) in Rio Grande do Sul]]> Abstract This study aimed to evaluate the genetic and cytological diversity and stability of 35 cherry tree accessions collected in Rio Grande do Sul. We used 15 RAPD (Random Amplified Polymorphic DNA) molecular markers and performed cytological analysis and number count of anthers. Analyses of genetic diversity allowed the separation of accessions into four groups, resulting in an average of 8.93 bands per primer amplified, 7.89 polymorphic bands, 88.08% of polymorphism and 86% of genetic similarity. Cytological analyses of gametic cells allowed for the characterization of accessions as diploids with n=11. In these, the average of meiotic cells considered normal was 82.12%; average pollen viability was 92.44% and in vitro germination was 40.26%; the average number of anthers was 161.85 anthers/flowers. Therefore, the accessions evaluated showed high genetic similarity and cytological stability and can be used in commercial plantations or hybridizations. <![CDATA[Resistance to Fusarium wilt in common bean]]> Abstract In breeding programs, understanding the potential of parents should be a way to spend significantly less time and costs to obtain new cultivars. For this, the objective of this study was to estimate the general and specific combining ability of parents aiming common bean breeding for resistance to Fusarium wilt (FW) based on disease severity and reduction in plant growth. Eight common bean genotypes were crossed in a 3 x 5 partial diallel mating scheme to obtain F1 hybrids. The parents and their 15 F1 hybrids were evaluated for severity of Fusarium wilt, area under the disease progress curve, percentage of plant height reduction and plant shoot fresh weight reduction and grain yield. The resistance of common bean to FW is controlled by a few dominant genes. The reduction in plant growth is controlled by a different set of genes that can increase the selection efficiency of parents for common bean breeding. <![CDATA[Application of microsatellite markers to confirm controlled crosses and assess genetic identity in common bean]]> Abstract This manuscript reports on the application of microsatellite markers to assess the effectiveness of controlled crosses and assess the genetic identity of seed samples from a same common bean cultivar (BRS Estilo). The DNA was extracted from leaf tissue collected from F1 plants and their parents as well as from seed samples of the cv. BRS Estilo by the alkaline lysis method. In all cases, genotyping was carried out with 24 microsatellite markers distributed in four multiplex panels with six markers each. Of the 392 F1 plants analyzed, obtained from 21 different biparental crosses, 325 (82.91%) was confirmed as real hybrids by the molecular analysis. The genetic analysis of the four BRS Estilo seed samples (two of certified seeds and two of saved seeds) detected 100.00% genetic identity with the samples used as control in only one certified seed sample. <![CDATA[Be-Breeder - Learning: a new tool for teaching and learning plant breeding principles]]> Abstract The Be-Breeder application is an on-line tool constructed through the R software for the purpose of assisting in some of the main genetic and statistical analyses related to the area of plant breeding. In addition, Be-Breeder provides a section called "Learning", which in a simple click-point manner allows explanation of theories related to the effect of inbreeding, population structure, qualitative and quantitative traits, heterosis, population size, effect of selection, and composition of hybrids. Be-Breeder is available for network use on the website of the Allogamous Plant Breeding Laboratory (Laboratório de Melhoramento de Plantas Alógamas) of ESALQ-USP through the link: <![CDATA[CD 1104 - extra strong wheat with high yield potential]]> Abstract CD 1104 is a cultivar indicated for the wheat-producing regions 1, 2, 3, 4 (irrigated) and 4 (rainfed) of the states of RS, SC, PR, SP, MS, MG, DF, GO, and MT. Its suitability for the industrial segment of strong flours and yield potential (mean of 4.427 kg ha-1) are high. <![CDATA[UENF Rio Dourado: a new passion fruit cultivar with high yield potential]]> Abstract This work aimed at introducing the characteristics of the passion fruit cultivar UENF Rio Dourado, developed from three cycles of recurrent selection, to the scientific community. The cultivar presents yield of 25 tons ha-1, mean values of 250 for number of fruits and 175g for fruit weight, providing a percentage increase in yield, number of fruits and fruit weight of 36%, 25% and 3%, respectively, when compared to the standard cultivar tested. <![CDATA[URS Altiva - a new oat cultivar with high agronomic performance]]> Abstract The oat cultivar URS Altiva, developed from the simple cross 'UFRGS 995090-2 x URS 21', and released by the Oat Breeding Program of the Federal University of Rio Grande do Sul (UFRGS) in 2015, presents high grain yield, high grain quality, desirable agronomic performance, and partial resistance to crown rust. <![CDATA[BRSMG Uai: common bean cultivar with carioca grain type and upright plant architecture]]> Abstract The common bean cultivar with carioca grain type, BRSMG Uai, is recommended for cultivation in Minas Gerais and stands out for its upright plant architecture, which facilitates cultivation and mechanical harvesting. This cultivar has high yield potential and is resistant to the major races of anthracnose that occur in region.