Evaluating sources of variability in inflorescence number, flower number and the progression of flowering in Sauvignon blanc using a Bayesian modelling framework

The time of flowering is key to understanding the development of grapevines. Flowering coincides with inflorescence initiation and fruit set, important determinants of yield. This research aimed to determine between and within-vine variability in 4-cane-pruned Sauvignon blanc inflorescence number per shoot, number of flowers per inflorescence and flowering progression using an objective method of assessing flowering via image capture and statistical analysis using a Bayesian modelling framework. The inflorescence number and number of flowers per inflorescence were measured by taking images over the flowering period. Flowering progression was assessed by counting open and closed flowers for each image over two seasons. An ordinal multinomial generalised linear mixed-effects model (GLMM) was fitted for inflorescence number, a Poisson GLMM for flower counts and a binomial GLMM for flowering progression. All the models were fitted and interpreted within a Bayesian modelling framework. Shoots arising from cane node one had lower numbers of inflorescences compared to those at nodes 3, 5 and 7, which were similar. The number of flowers per inflorescence was greater for basal inflorescences on a shoot than apical ones. Flowering was earlier, by two weeks, and faster in 2017/18 when compared to 2018/19 reflecting seasonal temperature differences. The time and duration of flowering varied at each inflorescence position along the cane. While basal inflorescences flowered later and apical earlier at lower insertion points on the shoot, the variability in flowering at each position on the vine dominated the date and duration of flowering.This is the first study using a Bayesian modelling framework to assess variability inflorescence presence and flower number, as well as flowering progression via objective quantification of open and closed flower counts rather than the more subjective method of visual estimation in the field or via cuttings. Although flower number differed for apical and basal bunches, little difference in timing and progression of flowering by these categories was observed. The node insertion point along a shoot was more important. Overall, the results indicate individual inflorescence variation and season are the key factors driving flowering variability and are most likely to impact fruit set and yield.

Timing and Rates of Two Products Using Hydrogen Peroxide (H2O2) to Control Algae in Ebb and Flow Hydroponic Systems

Algae is not desirable in hydroponics and creates problems such as reduced yield and decreased dissolved oxygen, and affects the physiology of plants and, thus, needs to be controlled. An experiment was conducted in Ebb and Flow hydroponic systems to investigate the application timing and rates of two hydrogen peroxide products (Zerotol and PERpose Plus). Treatments included 35 mL weekly, 35 mL biweekly, 70 mL weekly, 70 mL biweekly, and a control with no application of hydrogen peroxide using a 40-gallon reservoir of water. Pepper ‘Early Jalapeno’ and ‘Lunchbox Red’ and tomato ‘Geronimo’ and ‘Little Sicily’ were used. The study was conducted in a split-plot design with two replications over time. Plant growth parameters, including plant height, flower number, net CO2 assimilation, fresh weight, and dry weight were recorded. Algae data, including dry weight, algae cell counts, and chl a were also measured. Results indicated that with increasing rate and timing of either product decreased algae counts, dry weight, and chl a values. However, weekly and biweekly application of 70 mL of both products were not different for algae quantification. In pepper, plant height, shoot fresh and dry weight, and root fresh and dry weight were found to be significantly greater with Zerotol 35 mL biweekly, Zerotol 70 mL weekly, PERpose Plus 35 mL biweekly, and PERpose Plus 70 mL weekly compared with the control. ‘Lunchbox Red’ was significantly greater than ‘Early Jalapeno’ in all growth parameters, except soil plant analysis development (SPAD). ‘Lunchbox Red’ had the greatest flower number, with weekly application of 70 mL PERpose Plus. In tomato, greatest flower number and SPAD were observed in ‘Geronimo’ with a weekly application of 70 mL PERpose Plus and 70 mL Zerotol, respectively. Greater shoot and root fresh and dry weight for both tomato cultivars were recorded with 35 mL biweekly or 70 mL weekly application with either product. The results from both plants as well as algae analysis suggest that weekly application of 70 mL of either Zerotol or PERpose Plus produced the best results in terms of controlling algae and improving the growth of pepper and tomato plants.

Analysis of Morphological Characteristics and Variation in Five Populations of Zabelia tyaihyonii in South Korea

Background and objective: Native to the limestone zones of the Korean Peninsula, Zabelia tyaihyonii is a popular plant for landscaping. As it is now classified as a rare species, the conservation of its genetic resources is necessary.Methods: In this study, which aimed to understand the morphological variation of Z. tyaihyonii, 18 characteristics of Z. tyaihyonii from five habitats were examined.Results: Of these 18 characteristics, 16 characteristics showed significant differences among sites, and the coefficient of variation ranged from 5.4% (for corolla lobe number) to 31.3% (for flower number). Notable variations were observed in the size of flower and calyx lobe. When the corolla length and calyx lobe length were used as the classification key of Z. tyaihyonii, the sites were divided into those with small, intermediate, and large values. Hair was observed on the filament of all samples, a finding which conflicts with an earlier report. Rather than classifying Z. tyaihyonii into different species on the basis of corolla length (COL) and calyx lobe length (CALL) values, we recommend modifying the species description to incorporate the variation in these characteristics of interest. Principal component analysis results showed that the first main component was highly correlated with the traits related to the size of the calyx lobe (length: 0.819, width: 0.758), and the second main component was highly correlated with the traits related with the size of the inflorescence (length: 0.790, width: 0.626).Conclusion: Several notable variations were identified among the characteristics related to inflorescence and calyx lobe. There is little genetic exchange among groups, or each group is influenced by micro environmental factors, because sites that are located nearby. In addition, the difference between COL and CALL, which is used as the classification key for Z. tyaihyonii, was divided into small group, large group, and intermediate group, regardless of the sites’ geographical distance.

Reproductive Success of an Endangered Plant after Invasive Bees Supplant Native Pollinator Services

Arctomecon humilis (dwarf bear poppy) is an endangered gypsophile restricted to the St. George area in southern Utah, USA. Extirpation of the rare oligolectic bee Perdita meconis and decline of other native pollinators within the last 20 years has been largely attributed to the advent of invasive Africanized honeybees (AHBs), which have become the predominant pollinator for A. humilis. A three-year study was carried out to determine if reliance on AHBs had a negative effect on reproductive output. In the first year, pollen addition experiments were carried out in a small, isolated population to determine if pollinator scarcity or genetic factors affected reproductive output. In the subsequent two years, reproductive output studies were conducted across four populations. In all years, fruit set across study sites was exceptionally high. There was no consistent effect from flower number or interplant distance, which have historically been shown to have a significant impact on reproductive output prior to AHB arrival. The consequences and sustainability of this relatively young relationship between A. humilis and the AHB remain unclear. However, high reproductive success shows that the AHB is currently capable of adequately fulfilling pollinator services for A. humilis.

An ethylene biosynthesis enzyme controls quantitative variation in maize ear length and kernel yield

Maize ear size and kernel number differ among lines, however, little is known about the molecular basis of ear length and its impact on kernel number. Here, we characterize a quantitative trait locus, qEL7, to identify a maize gene controlling ear length, flower number and fertility. qEL7 encodes 1-aminocyclopropane-1- carboxylate oxidase2 (ACO2), a gene that functions in the final step of ethylene biosynthesis and is expressed in specific domains in developing inflorescences. Confirmation of qEL7 by gene editing of ZmACO2 leads to a reduction in ethylene production in developing ears, and promotes meristem and flower development, resulting in a ~13.4% increase in grain yield per ear in hybrids lines. Our findings suggest that ethylene serves as a key signal in inflorescence development, affecting spikelet number, floral fertility, ear length and kernel number, and also provide a tool to improve grain productivity by optimizing ethylene levels in maize or in other cereals.

Studies on Varietal Diversity and Selection of Potential Varieties of Gerbera (Gerbera Jamesonii H. Bolus Ex Hook. F.) For Commercial Cultivation in Bangladesh

Ten commercial genotypes of Gerbera jamesonii were evaluated for a number of qualitative and quantitative traits in RCBD at the Botanical Garden of Jahangirnagar University, Savar, Dhaka. Qualitative morphology among 10 genotypes showed significant similarities and dissimilarities. The analysis of variance for all the quantitative traits showed highly significant variations among the genotypes. Genotypes Dutch Diva, Classic Fabio Gold, Candela and Dune proved to be the most suitable and sustainable as they were the best performer for different growth and flower quality parameters. Number of flowers per plant found best in Candela and Dutch Diva (11.33). The phenotypic coefficients of variation (PCV) were found higher than the genotypic coefficients of variation (GCV) for all characters. Maximum GCV and PCV were observed for number of suckers per plant (30.984 and 39.568) followed by number of whorls of ray florets per flower and days to flowering from bud initiation. High heritability values were obtained for all the characters. In high heritability estimate coupled with high genetic advance as percentage of mean was maximum for days to first flowering (32.442), plant height (cm) (17.026) and number of suckers per plant (15.992). Selection would be effective for the character showing high performance in genetic parameter. Path analysis revealed that the diameter of disc florets per flower, stalk girth (cm), number of disc florets per flower, number of ray florets per flower would be selection criteria for improvement in flower number. Based on D2 statistics, 10 genotypes were grouped into 3 clusters, namely cluster I, II and III. Highest number of genotypes was found in cluster I containing 5 genotypes. Scatter diagram represents pattern of genotypic distribution into clustering through principal component scores. Highest inter-cluster distance (22.94) was observed between cluster I and III. The genotypes of cluster II possessed heterogeneous nature and showed highest intra-cluster distance (11.35). Highest cluster mean was observed in cluster II containing four genotypes regarded as the superior than another cluster. Bangladesh J. Bot. 50(3): 541-550, 2021 (September)

Yield of Spring Grown Chickpea (Cicer arietinum L.) under Different Doses of Soil Applied Phosphorus in An Agroecology of Semi-arid Highlands with Mediterranean Climate

Background: This study was carried out to determine the effects of different phosphorus doses on the flowering, yield and yield components of spring grown chickpea crop under the ecological conditions of Siirt province in the experimental field of Siirt University, Faculty of Agriculture, Field Crops Department during two seasons in 2018 and 2019. Methods: The study was carried out in randomized complete blocks design with three replications. Before planting, 140 kg ha-1 of DAP fertilizer (18.46.0) was spreaded and incorporated into the soil with a rake. Following emergence of plants, TSP fertilizer (0.42.0) was spreaded to the plots at doses of 0, 30, 60, 90 kg ha-1 P2O5 into the mellow humid soil. Result: All observed parameters were effected from phosphorus application doses. Based on different P doses, two years’ average plant height, first pod height; main branch number, flower number per plant, pod number per plant, grain number per plant, 100 grain weight and grain yield values were determined as 51,25-55,91 cm; 29,17-35,98 cm; 2,10-2,97 piece plant-1; 39,00-57,86 piece plant-1; 18,87-27,92 piece plant-1; 18,00-27,33 piece plant-1; 29,92-33,41 g and 969-1565 kg ha-1, respectively. Highest values for all parameters were obtained from 60 kg ha-1 P2O5 but further dose (60 kg ha-1 P2O5) resulted with reduction from top values for all parameters.