Resumo em Inglês:

Abstract The objective of the study was to determine whether Parkia platycephala families with superior morphophysiological traits perform consistently across four stages of early development (plantlets, seedlings, and juveniles at 34 and 60 months), as a means to assess the possibility of conducting pre-selection. For 21 morphophysiological traits, the following genetic parameters were estimated: heritability, coefficients of variation (genetic, relative, and environmental), accuracy, genetic and phenotypic correlation, percentage of coincidence (PC) of the best families, effective population size, and inbreeding in three progeny tests conducted under laboratory, nursery, and field conditions. Families of P. platycephala showed significant phenotypic and genotypic differences. The traits evaluated show genetic control. The percentage of coincidence between the best families was more accurate when the selection intensity was greater than 50% (PC ≥ 52%). Based on the evaluated traits, a pre-selection strategy at the juvenile stage for P. platycephala was researched to effectively identify superior families.

Resumo em Inglês:

Abstract Fusariosis (Fusarium guttiforme) is the most destructive disease of the pineapple crop in Brazil. The aim of this study was to evaluate the reaction to an isolate in pineapple genotypes selected for crownless fruit weight (CFW) and total soluble solids (TSS). A total of 1,125 genotypes ('BRS Imperial'×'Pérola') were evaluated. Selection for greatest CFW and TSS was performed during the sexual cycle. The isolate was inoculated on slip-type plantlets using the immersion technique. Plantlets were evaluated for disease intensity in the stem, attributing scores from 0 to 5. Eighteen genotypes were selected with values from 1.514 to 3.307 g (CFW) and from 14.6 to 19.4 °Brix (TSS). Six genotypes reached the highest level of survival against the IT-01 isolate. Selected genotypes have agronomic traits superior to those of their parents, which qualify them to be cycled back into the plant breeding program of the Instituto Agronômico de Pernambuco - IPA.

Resumo em Inglês:

Abstract Tomato Fusarium wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) constrains tomato production worldwide. Three hundred forty tomato accessions were evaluated for Fusarium wilt resistance and single nucleotide polymorphisms (SNPs) associated with resistance. The disease resistance evaluation revealed that 15, 13, and 15 accessions were identified as Fusarium wilt resistant in Test 1, 2, and Mean data, respectively, with the disease severity index (DSI) ranging from 0-16.7%. A genome-wide association study (GWAS) identified SNPs associated with resistance. Eighteen common SNPs were detected in at least two tests and located on chromosomes 4, 6, 7, 9, and 12. Six unique significant SNPs were found in either Test 1 or 2, located on chromosomes 2, 4, and 7. Candidate genes associated with Fusarium wilt resistance were identified. Notably, two genes encoding leucine-rich repeat-like protein and disease-resistance protein were predicted from the two unique SNPs, solDsnp10606 and solDsnp6266, respectively.

Resumo em Inglês:

Abstract The successful transfer of R-cytoplasm (Ogura)-induced cytoplasmic male sterility has aroused great interest in the development of hybrids in cabbage. An experiment was conducted from 2018 to 2020 to study the per se performance and estimate heterosis in cabbage (Brassica oleracea L. var. capitata L.), This crop is highly cross-pollinated; thus, exploitation of heterosis is an additional advantage. The experimental material consisted of an F1 population of 18 crosses, resulting from three lines (CMS) crossed with six testers in a Line × Tester design, plus a standard check (Pusa Cabbage Hybrid-1). The per se performance and estimates of heterosis of the cross combinations L1 × T2, L2 × T2, L2 × T5, L3 × T2 and L3 × T5 were high for various horticultural parameters. Hence, after multilocation testing, these parents and crosses can be released to substitute existing cabbage varieties/hybrids.

Resumo em Inglês:

Abstract The induction of polyploidy in Eucalyptus can lead to higher-yielding and more adapted clones, with better wood quality. After artificial polyploidization, it is necessary to certify the effectiveness of the process through cytogenetic analyses and anatomical trait evaluations. Thus, the aim of this study was to certify the chromosome duplication in artificially polyploidized clones of Eucalyptus grandis × Eucalyptus urophylla using cytogenetic analysis, flow cytometry, and leaf anatomy measurements. Chromosomal counts and DNA content estimation allowed the identification of artificially polyploidized clones and mixoploids. Polyploid clones had larger stomata diameter than diploids. The increase in stomata size was accompanied by lower stomatal density in most polyploid clones. The typical gigas effect of polyploidized plants was demonstrated by the expressive increase in leaf area in polyploid individuals compared to diploids. Our findings indicate that the use of polyploidy in Eucalyptus breeding is promising, allowing the discrimination of diploid, tetraploid, and mixoploid plants.

Resumo em Inglês:

Abstract Rusts and powdery mildews pose serious threats to wheat and have caused substantial yield losses worldwide. Host resistance is the most economical and sustainable approach for managing such diseases. In this study, an effective leaf rust resistance gene Lr45-derived from Secale cereale L. and a linked stem rust and powdery mildew resistance gene Sr36/Pm6-derived from Triticum timopheevii were successfully pyramided. They were validated into well-adapted Indian wheat cultivars that were already carrying the APR stem rust gene Sr2/Lr27/Yr30 through marker-assisted backcross selection (MABC) following two parallel backcrossing schemes. Three efficiently linked microsatellite markers, G372185 (Lr45), Stm773-2(Sr36), and Xgwm533 (Sr2), were used to confirm introgression of these genes. Lines with resistance genes in each background showed improved agronomic traits in comparison to their recurrent parents. These lines could be used in wheat improvement programs as potentially resistant stocks for leaf, stem rusts and powdery mildew to develop new wheat cultivars.

Resumo em Inglês:

Abstract The germination potential must be considered in the selection of passion fruit genotypes, since vigorous seeds originate seedlings with a higher growth rate, resulting in superior plants with high agronomic performance. This study proposes to estimate genetic parameters and selection gain for seed traits of full-sib families (FSF) of passion fruit under recurrent selection for resistance to the cowpea aphid-borne mosaic virus (CABMV). Physical and physiological seed traits of 86 FSF were evaluated; genetic parameters, genotypic correlations between traits and genetic gains were estimated using four selection indices. There were significant differences and genetic variability between families and positive genetic correlations between variables. The best distribution of genetic gains was obtained by the Mulamba and Mock index, using the heritability coefficient and arbitrary weights. This index selected the best 26 families in terms of seed characteristics to compose the second cycle of recurrent selection for resistance to CABMV.

Resumo em Inglês:

Abstract Rhododendron henanense subsp. lingbaoense Fang (Rhl) is a subspecies endemic to China with important ornamental value. Recently, the Rhl population has been shrinking as a result of its limited distribution range, poor natural regeneration, and rising human exploitation. In this study, high-quality single nucleotide polymorphisms (SNPs) identified through whole-genome resequencing were examined in 50 individuals from four populations of Rhl with a depth of ~34× to evaluate genome-level diversity and population structure. Population structure profiling, principal component analysis, and phylogenetic analysis clustered the Rhl samples into two groups corresponding to their geographical distributions. Analysis of SNPs indicated that Rhl populations have high genetic diversity and little genetic differentiation. Additionally, demographic history indicated that all four populations of Rhl have experienced long-term population decline. The above findings showed that we should take action to protect this rare species.

Resumo em Inglês:

Abstract This study aimed to apply, in unprecedented depth, a Bayesian approach to the non-linear regression model developed by Toler for evaluating the stability and adaptability of genotypes. Twenty-five soybean cultivars were evaluated in twenty-one plots across the midwestern of Brazil. A complete block design was employed, with three replications. The evaluated variable was grain yield. The proposed methodology was implemented in the R program by means of the BRugs package. The methodology was capable of differentiating the effect of the environment on soybean cultivars in terms of yield in the different environments, allowing exploration of the response of each genotype to environmental variations. Cultivars 6266RSF, NS6990, GD19I435, GD19I439, GD19C443, RC0496 and IA18661 presented good stability and general adaptability, being the most recommended for future evaluations. The other cultivars presented specific adaptability and high responsiveness to unfavorable environments.

Resumo em Inglês:

Abstract ‘SCS453 Noninha’ and ‘SCS454 Carvoeira’ are new banana cultivars derived from the subgroup Prata (AAB). In comparison with the latter, ‘SCS453 Noninha’ has a low pseudostem height, 'SCS454 Carvoeira' a high yield and both unchanged fruit characteristics. Both also have increased resistance to Panama wilt and ‘SCS454 Carvoeira’ to Sigatoka.

Resumo em Inglês:

Abstract The hybrids are responsive to phosphorus application, have high use efficiency and can produce high mean yields in environments with low and high phosphorus. The mean PE of these hybrids is high, therefore they are recommended for cultivation in the North and Northwest regions of Rio de Janeiro State, Brazil.

Resumo em Inglês:

Abstract BRS Rendeira and BRS Progresso are cassava (Manihot esculenta Crantz) cultivars with tolerance to post-harvest deterioration and high mean yields of fresh root (31.1 and 27.9 t ha-1) and starch (8.9 and 8.1 t ha-1) in annual production cycles. Both new varieties are recommended for the flour and starch industry.