Phenotypic variability of cowpea genotypes for immature seed harvesting

ABSTRACT Seed color, brightness and texture are important aspects for the consumption of immature beans. This study aimed to estimate the phenotypic variability among thirty cowpea genotypes for immature seed harvesting, in order to guide breeding programs. The experiment was carried out in a randomized blocks design, with three replications. The evaluated traits were immature seeds yield, pods and dry seeds production, number of immature pods, 100-immature seeds weight, immature pods length, number of seeds per immature pod, cooking time, harvesting period of immature pods, seed color, pod color, plant growth habit, opening of immature pods, seed threshing from immature pods, cultivation value and seed browning after threshing. Anova and three clustering methods were applied: UPGMA using the Jaccard coefficient of similarity; modified Tocher method based on the Gower algorithm; and k-means. All the analyses were performed based on the variable means of experiments evaluated in six environments. A statistically significant phenotypic variability was observed among all the quantitative traits. Discrepancies occurred in the accessions grouping and number of clusters. The accession BRS Acauã, in one group, and P508 and PCCR3F6L15, in other groups, showed a good quality for immature grain harvesting, were consistently grouped into different clusters and are recommended for use as parents in the development of new cultivars.

An analysis of the physiological impacts on life history traits of peanut (Arachis hypogaea L.) related to seed maturity

ABSTRACT Peanut is an important oilseed crop and legume species, with more than 1.9 M tons produced annually in the U.S. Being indeterminate, peanut continually flowers and sets pods throughout the growing season, leading to the potential harvest of both mature and immature pods. To quantify the physiological impacts of peanut seed maturity, a two-year field study was conducted to elucidate the difference in canopy structure and reproductive characteristics, including flower production, yield, and grade between seed obtained from immature and mature seed of two commercial peanut cultivars: TUFRunner™ ‘727’ and FloRun™ ‘107’. Data indicated that seed from the yellow class of pods have lower vigor and overall plant development and performance; further, plants developed from immature seed never achieved a level of performance comparable to that of the mature brown/black pod classes. There were differences between cultivars in the severity of the impact of immaturity, with larger detrimental effects on immature TUFRunner™ ‘727’, which exhibited reduced emergence. Despite these cultivar differences, this study illustrated that mature seed performs better in a field setting than immature seed. These results are critically important to disproving the ‘catch-up' assumption: seed maturity not only has an impact on emergence, but on subsequent life history and performance traits through the remainder of the season.

Validation of reference genes for gene expression studies in tartary buckwheat (Fagopyrum tataricum Gaertn.) using quantitative real-time PCR

Quantitative real-time reverse transcriptase polymerase chain reaction is a sensitive technique for quantifying gene expression levels. By implementing three distinct algorithms (geNorm, normFinder and BestKeeper), we have validated the stability of the expression of seven candidate reference genes in tartary buckwheat, including FtSAND, FtCACS, FtExpressed1, FtGAPDH, FtActin, FtEF-1a and FtH3. In this study, the results indicated that FtCACS and FtSAND were the best reference genes for ‘abiotic cotyledons’, FtExpressed1 and FtEF-1α were the best reference genes for aluminium treatment, FtCACS and FtExpressed1 performed the best for the immature seed stage, FtCACS was best for the abiotic treatment, and FtH3 appeared to be the most suitable reference gene for the abiotic treatment in hypocotyls and all samples in this study. In contrast, FtActin and FtGAPDH are unsuitable genes. Our findings offer additional stable reference genes for gene expression research on tartary buckwheat at the immature seed stage and under abiotic treatment.

Effect of Seed Maturity and Storage Duration on Germination of Sambiloto (Andrographis paniculata (Burm.f.) Nees)

<p>Seed maturity and its storage are one of problems on propagation and developing of medicinal plants such as sambiloto (<em>Andrographis paniculata </em>(Burm.f.) ex Nees). The research aimed to determine effects of seed maturity and storage duration on seed germination of sambiloto was conducted in a green house of Purwodadi Botanical Garden from November 2014 to November 2015. The experiment done by completely randomised design with two treatments namely seed maturity and storage duration. The seed was classified into immature seed (0.061 g/100 seeds), semimature seed (0.113 g/100 seeds) and mature seed (0.166 g/100 seeds). The seed’s storage duration was classified into seed was not stored, seed was stored for six months and seed was stored for twelve months. Each treatment combination was replicated five times. The results showed that there were significant interactions between the treatments on percentage and rate of seed germination. The highest percentage of seed germination was the treatment of mature seed and stored twelve months (98.50%). On the contrast, the lowest seed germination percentage was the treatment of immature seed and stored twelve months (4.25 %). The fastest seed germination rate was the treatment of mature seed and stored six months (3.88 days), whereas the slowest seed germination rate was the treatment of immature seed and without stored (28.58 days). This study is expected to be applied to improve genetic and cultivation of medicinal plant as well as increasing plant growth and yield.</p>

Pod Maturity in the Shelling Process

ABSTRACT Determining an optimum harvest maturity for indeterminate crops such as peanut is critical because it directly affects yield and grade. Historically, the assumption has been that growers will harvest at optimum maturity due to the positive impact on these two characteristics. However, the increased acreage under management by a single farmer may cause growers to harvest prior to optimum maturity. The impact of peanut maturity on seed quality may not be fully understood by producers, where immature seed may have reduced emergence and vigor. Research was conducted to quantify the maturity of seed peanuts received by the Florida Foundation Seed Producers, Inc. (FFSP) at various stages of the shelling process: samples received from the field; after the in-shell samples were cleaned; after in-shell pre-sizing into two size classes; and after separation of in-shell samples at the gravity deck. Samples collected at each stage were pressure-washed to remove the exocarp and then separated into yellow and brown/black color classes based on the maturity board. Pods within each color class were counted, dried, weighed, and graded. Maturity at each sheller stage was assessed for three peanut cultivars. For the field stage, across all cultivars, 56% of pods were in the mature, or brown/black color class. This was well below the level of 70-80% in the brown/black class purported to be the maturity level that optimizes yield and grade. Cleaning had a minor impact on maturity percentages (average percent mature was 64% across all cultivars after passing through the mechanical cleaning process); however, in the pre-shelling sizing process where pods are sorted into “lead” and “small” baskets representing large and small pods, respectively, the maturity percentage was improved to 75% in the large pods and declined to 45% in the small pods. These results indicate that: 1) maturity levels of cultivars harvested in the field may not be optimal; and 2) that improvements could be made in maturity percentages by modifying the shelling process to separate the larger pods which are more likely to be mature than the smaller pods. These results also suggest that seed peanut lots are unlikely to be composed entirely of mature pods, that large numbers of immature pods could make it through the shelling process and that immature seed are planted by farmers. This could explain some cases of suboptimal plant stands in peanut.