Availability of floral resources in yellow passion fruit cultivars

The reproductive strategies and resources available in the flower are characteristics that stimulate research studies on the genetic improvement and fruit yield of commercial cultivars. In this sense, this study aimed to study the floral biology aspects of passion fruit cultivars in Tangará da Serra region, Mato Grosso State, Brazil at different evaluation times. The experiment was carried out with eight cultivars of yellow passion fruit from an ex situ germplasm bank of the State University of Mato Grosso. The floral resources (pollen and nectar) were evaluated in a completely randomized, factorial arrangement (8 cultivars x 5 evaluation times), with five replications. Throughout anthesis, the pollen viability, stigma receptivity, and sugar volume and concentration in the nectar were evaluated. The evaluations were carried out in 1-h intervals, between 1:30 and 5:30 p.m. The highest nectar volume production was at 2:30 p.m., decreasing gradually thereafter at the later evaluation times, for all cultivars. Pollen viability increased from the first to the second evaluation time and then decreased gradually until the last evaluation. Stigma receptivity was higher than 90% in all cultivars, at all evaluation times. BRS Rubi do Cerrado and FB 200 were the most promising cultivars for nectar volume and concentration, pollen viability, and stigma receptivity characteristics.The reproductive strategies and resources available in the flower are characteristics that stimulate research studies on the genetic improvement and fruit yield of commercial cultivars. In this sense, this study aimed to study the floral biology aspects of passion fruit cultivars in Tangará da Serra region, Mato Grosso State, Brazil at different evaluation times. The experiment was carried out with eight cultivars of yellow passion fruit from an ex situ germplasm bank of the State University of Mato Grosso. The floral resources (pollen and nectar) were evaluated in a completely randomized, factorial arrangement (8 cultivars x 5 evaluation times), with five replications. Throughout anthesis, the pollen viability, stigma receptivity, and sugar volume and concentration in the nectar were evaluated. The evaluations were carried out in 1-h intervals, between 1:30 and 5:30 p.m. The highest nectar volume production was at 2:30 p.m., decreasing gradually thereafter at the later evaluation times, for all cultivars. Pollen viability increased from the first to the second evaluation time and then decreased gradually until the last evaluation. Stigma receptivity was higher than 90% in all cultivars, at all evaluation times. BRS Rubi do Cerrado and FB 200 were the most promising cultivars for nectar volume and concentration, pollen viability, and stigma receptivity characteristics

Genetic divergence in snap bean based on agronomic traits and resistance to bacterial wilt

The objectives of this research were to estimate the genetic divergence among genotypes of bush snap beanwith based on morphoagronomic descriptors and evaluation of resistance to bacterial wilt; to determine the relative importanceof the distinguishing traits of genotypes and to indicate potential parents to establish a snap bean breeding program forresistance to bacterial wilt. Two experiments were conducted, the first in the field and the second in a greenhouse, both with 15genotypes in a randomized block design with three replications. Seven traits were studied in the field experiment: days toflowering; days to harvest; mean pod length; number of pods; number of pods per plant; total pod weight and number of seedsper pod. In the greenhouse, the reaction of bacterial wilt was assessed based on two variables, one based on a descriptivegrade scale and the other based on the Area Under the Disease Progress Curve (AUDPC). For the evaluation of genotyperesistance to bacterial wilt the isolate Feij – 2634 of Curtobacterium flaccumfaciens pv. flaccumfaciens was inoculated. Thestatistics of pseudo t2 indicated the formation of four groups by the UPGMA method, the same number of groups as indicatedby the use of canonical variables. The traits that contributed most to genetic divergence were days to harvest, pod length, poddiameter and AUDPC

Morphological and molecular characterization of native Heliconia sp. accessions of the Amazon region

Heliconias are tropical plants with ornamental potential. These plants are particularly used in the floriculture industry because of their exotic colors and shapes. Species characterization is important for the selection of genotypes for the ornamental plant market and subsequent application in studies of genetic improvement. The aim of this study was to estimate the genetic divergence of Heliconia densiflora and Heliconia psittacorum accessions based on quantitative morphological and molecular markers. The mor- phological and molecular descriptors revealed genetic variability among the accessions evaluated. The greatest genetic variability was observed among H. psittacorum accessions, whose sample number was also larger compared to H. densiflora. Morphological characterization was efficient in differentiating the two Heliconia species, especially to characteristics such as bract and inflores- cence length, postharvest durability, and flower stem diameter, which contributed most to the divergence in this study. On the other hand, molecular characterization identified one H. densiflora individual that was grouped with the H. psittacorum genotypes. The results showed that ISSR markers can differentiate closely related H. densiflora and H. psittacorum individuals. The materials evaluated can contribute to the maintenance of local genetic diversity through the germplasm bank of the local breeding program of ornamental tropical plants

Agriculture calendar for the maize crop in Sinop, Mato Grosso State, Brazil

This study aimed at determining an agriculture calendar for the maize crop in Sinop, Mato Grosso State, Brazil, by evaluating rainfall, air temperature and evapotranspiration. Based on the thermal requirements of the maize hybrid, the heat unit accumulation or degree-day methods were used to determine the occurrence of phenological stages, considering the highest (30ºC) and lowest (10ºC) temperatures. The growing season was determined by analyzing the variation of the total 10-days average rainfall and evapotranspiration for that locality. The calendar was established according to the thermal requirements to complete the phenological stages, rainfall distribution during these stages and probability of occurring at least five dry days per 10-days period. The best sowing time took place between the 30th and 32nd 10-days period, at the end of October and beginning of November

Secondary pollen presentation and foral traits of Heliconia psittacorum

The secondary presentation of pollen consists of a foral mechanism where the presentation of pollen occurs in other foral structures in addition to the anther, in order to increase the precision of the dispersion of the pollen by the vectors. This study aims to describe the temporal dynamics of secondary pollen presentation, and morphological and morphometric characteristics in stages of pre- anthesis and anthesis in genotypes of fve natural Heliconia psittacorum populations. For the study of foral morphometry traits of length of the fower, stamen, stigma and height of flament insertion in the petal in bud and fower were measured. The foral morphology of pre-anthesis buds and fowers in anthesis, the presence or absence of characteristics such as herkogamy, region of flament insertion in the petal, region of stylar hairs, and of secondary pollen deposition were evaluated. Treatments of controlled pollinations, self-pollination, geitonogamy, cross-pollination, natural pollination and growth to pollen tube were sampled. Floral herkogamy and pollen transfer to the adhered hairs in the stylar region were clearly observed during anthesis, constituting the frst record of occurrence of secondary pollen presentation in Heliconiaceae. Pollen tube growth was inhibited in the stigmatic, style and basal regions of the pistil. Natural fruiting produced little or no fruit. The positioning of the stamens above the stigma, pollen viability and stigma receptivity during anthesis of H. psittacorum fowers may favor self-pollination. The stylar hairs observed in all H. psittacorum populations’ help in the retention of pollen grains. The low fruiting rate in controlled and natural pollinations suggest that the main propagation form of H. psittacorum in the study areas is based on asexual reproduction

Productivity and fruit quality of yellow passion fruit cultivars with or without artificial pollination

O objetivo deste trabalho foi avaliar a influência da polinização artificial na produtividade e qualidade de frutos de cultivares de maracujazeiro‑amarelo. Foram utilizadas sete cultivares comerciais de maracujazeiro‑amarelo, em dois experimentos realizados na região de Tangará da Serra, MT, em delineamento de blocos ao acaso, com cinco repetições e parcelas constituídas por duas linhas de quatro plantas. No primeiro experimento, a polinização foi natural; no segundo, foi realizada a polinização artificial, duas vezes por semana. O plantio foi feito no dia 11 de janeiro de 2010 e as colheitas no período de julho de 2010 à março de 2011. A polinização artificial aumentou a produtividade de todas as cultivares, mas estas apresentaram diferentes sensibilidades à técnica. Quando a polinização artificial foi utilizada, as cultivares FB 100, FB 200 e BRS Ouro Vermelho tiveram maior rendimento do que IAC 275, IAC 277, BRS Sol do Cerrado e BRS Gigante Amarelo. A polinização artificial aumenta a produtividade, a massa de fruto, o diâmetro e comprimento de fruto e a percentagem de polpa, e reduz a espessura de casca. Há indicação de forte interação genótipo por ambiente, quanto à produtividade das cultivares avaliadas.The objective of this work was to evaluate the influence of artificial pollination on productivity and fruit quality of yellow passion fruit cultivars. Seven commercial cultivars of yellow passion fruit were evaluated in two experiments carried out in Tangará da Serra, MT, Brazil, in a randomized block design with five replicates and plots consisting of two rows of four plants. In the first experiment, pollination was natural, whereas in the second it was artificial, performed twice a week. Planting was done on January 11, 2010, and harvests occured from July 2010 to March 2011. Artificial pollination increase the productivity of all cultivars, but their response to the technique varied. When artificial pollination was used, the cultivars FB 100, FB 200 and BRS Ouro Vermelho had a higher productivity than IAC 275, IAC 277, BRS Sol do Cerrado e BRS Gigante Amarelo. Artificial pollination increases productivity, fruit mass, diameter and length of fruit, and pulp percentage, and it reduces peel thickness. Strong genotype by environment interaction may be occurring, as for the productivity of the evaluated cultivars

Selection gain in the intrapopulation genetic breeding of yellow passion fruit

O objetivo deste trabalho foi estimar o ganho de seleção associado a características agronômicas de importância no melhoramento intrapopulacional do aracujazeiro‑amarelo. O experimento foi realizado em campo, no Município de Terra Nova do Norte, MT, com a avaliação de 111 famílias de irmãos completos (FIC) e seis cultivares comerciais, utilizadas como testemunhas. Utilizou-se o delineamento de blocos ao acaso, com três repetições e quatro plantas por parcela. Foram avaliadas as seguintes características: produtividade, comprimento, diâmetro e peso médio dos frutos, percentagem e peso de polpa, espessura de casca e teor de sólidos solúveis. Para verificar a existência de variabilidade genética entre os genótipos, estimaram-se os parâmetros genéticos da população com base na média das famílias. Os 30 genótipos com o menor valor da soma de postos, de acordo com o índice de seleção de Mulamba & Mock, foram selecionados para estimar os ganhos genéticos. Observaram-se altos valores médios para as características e parâmetros genéticos avaliados nas 26 FIC e nas quatro testemunhas selecionadas. O uso do índice de seleção proporciona ganhos genéticos positivos em produtividade, percentagem e peso de polpa, comprimento, diâmetro e peso de frutos, e espessura de casca.The objective of this work was to estimate the selection gain associated to traits of agronomic importance, in the intrapopulation genetic breeding of yellow passion fruit. The experiment was carried out in the field, in Terra Nova do Norte, MT, Brazil, by evaluating 111 full‑sib families (FSF) and six commercial cultivars, used as controls. The experimental design was a randomized complete block, with three replicates and four plants per plot. The following traits were evaluated: productivity, fruit length, diameter and weight, pulp percentage and weight, skin thickness, and soluble solid content. In order to determine the genetic variability between genotypes, the population’s genetic parameters were estimated based on the means of the families. The 30 genotypes with the lowest sum of ranks, according to Mulamba & Mock’s selection index, were selected to estimate genetic gains. High mean values were observed for the evaluated characteristics and genetic parameters in the 26 FSF and in the four controls selected. The selection index provides positive genetic gains as to: productivity, pulp percentage and weight, fruit length, diameter and weight, and skin thickness

Características florais e polinizadores na qualidade de frutos de cultivares de maracujazeiro‑azedo

The objective of this work was to determine the floral traits of eight cultivars of sour passion fruit and identify their pollinators, as well as to evaluate the influence of natural pollination on fruit quality, in the region of Tangará da Serra, MT, Brazil. A completely randomized experimental design was carried out, with ten replicates and one flower per plot to evaluate morphometry, and with four replicates and five flowers per cultivar to determine the fruiting rate. The following parameters were evaluated: flower morphology and morphometry, flower longevity, frequency of floral visitors, natural fruiting rate, and fruit quality. Flower morphology and morphometry were compatible with pollination by large-size bees; they were also compatible with pollination by medium‑size bees for the cultivars IAC‑275‑Maravilha, IAC‑277‑Jóia, BRS SC1, BRS RC, and BRS GA1. The greatest flower longevity was observed for the IAC‑277‑Jóia, BRS GA1, BRS RC, and BRS OV1 cultivars. The frequency of bees as Xylocopa (2.0%) and Bombus (3.9%) was low, and 'BRS GA1' received the highest number of these bee visits. Natural fruiting rate was low (36.67%). Naturally pollinated fruit show physical traits compatible with those required by the market standards.O objetivo deste trabalho foi determinar as características florais de oito cultivares de maracujazeiro‑azedo e identificar seus polinizadores, bem como avaliar a influência da polinização natural na qualidade dos frutos, na região de Tangará da Serra, MT. Utilizou-se o delineamento inteiramente casualizado, com dez repetições e uma flor por parcela para avaliar a morfometria, e com quatro repetições e cinco flores por cultivar para determinar o índice de frutificação. Avaliaram-se os seguintes parâmetros: morfologia e morfometria floral, longevidade floral, frequência de visitantes florais, índice de frutificação natural e qualidade de fruto. A morfologia e a morfometria das flores foram compatíveis com a polinização por abelhas de grande porte; também foram compatíveis com a polinização por abelhas de médio porte nas cultivares IAC‑275‑Maravilha, IAC‑277‑Jóia, BRS SC1, BRS RC e BRS GA1. A maior longevidade floral foi observada nas cultivares IAC‑277‑Jóia, BRS GA1, BRS RC e BRS OV1. A frequência de abelhas como Xylocopa (2,0%) e Bombus (3,9%) foi baixa, e 'BRS GA1' recebeu o maior número de visitas destas abelhas. O índice de frutificação natural foi baixo (36,67%). Os frutos de polinização natural apresentam características físicas compatíveis com as exigidas pelo mercado consumidor