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Gleditsia sinensis is a dioecious perennial tree, with its fruit size directly impacting its economic value. Investigating the feasibility of hybridization between different Gleditsia varieties and the influence of parentage on fruit size is crucial. In this study, we compared the pollen viability of Gleditsia sinensis , Gleditsia japonica var. delavayi ( G. delavayi ), Gleditsia japonica and Gleditsia fera under long-term storage, and explored the feasibility of intraspecific and interspecific hybridization of Gleditsia sinensis . We also evaluated the genetic characteristics of parentage on the fruit size and fruit set rate of Gleditsia sinensis . The results indicated that dry storage at -80 °C is suitable for the long-term preservation of pollen for most Gleditsia varieties. Interspecific hybridization of G. sinensis is feasible, and hybridization wit h G. fera exhibits a high general combining ability for fruit size. Therefore, G. fera can serve as an excellent male parent for interspecific hybridization with G. sinensis . The phenotypic traits of the current generation’s pods are primarily influenced by the additive effects of the maternal parent and the non-additive effects of both parents. Pod length and width exhibit high heritability, while pod thickness has lower heritability and is more significantly influenced by non-additive effects.

In flowering plants, pollination, pollen tube growth, and fertilization are regarded as the first hierarchical processes of producing offspring. However, their independent contributions to fruit set and development remain unclear. In this study, we examined the effect of three different types of pollen, intact pollen (IP), soft X-ray-treated pollen (XP) and dead pollen (DP), on pollen tube growth, fruit development and gene expression in “Micro-Tom” tomato. Normal germination and pollen tube growth were observed in flowers pollinated with IP; pollen tubes started to penetrate the ovary at 9 h after pollination, and full penetration was achieved after 24 h (IP24h), resulting in ~94% fruit set. At earlier time points (3 and 6 h after pollination; IP3h and IP6h, respectively), pollen tubes were still in the style, and no fruit set was observed. Flowers pollinated with XP followed by style removal after 24 h (XP24h) also demonstrated regular pollen tubes and produced parthenocarpic fruits with ~78% fruit set. As expected, DP could not germinate and failed to activate fruit formation. Histological analysis of the ovary at 2 days after anthesis (DAA) revealed that IP and XP comparably increased cell layers and cell size; however, mature fruits derived from XP were significantly smaller than those derived from IP. Furthermore, there was a high correlation between seed number and fruit size in fruit derived from IP, illustrating the crucial role of fertilization in the latter stages of fruit development. RNA-Seq analysis was carried out in ovaries derived from IP6h, IP24h, XP24h and DP24h in comparison with emasculated and unpollinated ovaries (E) at 2 DAA. The results revealed that 65 genes were differentially expressed (DE) in IP6h ovaries; these genes were closely associated with cell cycle dormancy release pathways. Conversely, 5062 and 4383 DE genes were obtained in IP24h and XP24h ovaries, respectively; top enriched terms were mostly associated with cell division and expansion in addition to the ‘plant hormone signal transduction’ pathway. These findings indicate that full penetration of pollen tubes can initiate fruit set and development independently of fertilization, most likely by activating the expression of genes regulating cell division and expansion.

In strawberries, fruit set is considered as the transition from the quiescent ovary to a rapidly growing fruit. Auxin, which is produced from the fertilized ovule in the achenes, plays a key role in promoting the enlargement of receptacles. However, detailed regulatory mechanisms for fruit set and the mutual regulation between achenes and receptacles are largely unknown. In this study, we found that pollination promoted fruit development (both achene and receptacle), which could be stimulated by exogenous auxin treatment. Interestingly, auxin was highly accumulated in achenes, but not in receptacles, after pollination. Further transcriptome analysis showed that only a small portion of the differentially expressed genes induced by pollination overlapped with those by exogenous auxin treatment. Auxin, but not pollination, was able to activate the expression of growth-related genes, especially in receptacles, which resulted in fast growth. Meanwhile, those genes involved in the pathways of other hormones, such as GA and cytokinin, were also regulated by exogenous auxin treatment, but not pollination. This suggested that pollination was not able to activate auxin responses in receptacles but produced auxin in fertilized achenes, and then auxin might be able to transport or transduce from achenes to receptacles and promote fast fruit growth at the early stage of fruit initiation. Our work revealed a potential coordination between achenes and receptacles during fruit set, and auxin might be a key coordinator.

Background Cassava ( Manihot esculenta Crantz) is staple food and major source of calories for over 500 million people in sub-Saharan Africa. The crop is also a source of income for smallholder farmers, and has increasing potential for industrial utilization. However, breeding efforts to match the increasing demand of cassava are impeded by its inability to flower, delayed or unsynchronized flowering, low proportion of female flowers and high fruit abortions. To overcome these sexual reproductive bottlenecks, this study investigated the effectiveness of using red lights to extend the photoperiod (RLE), as a gateway to enhancing flowering and fruit set under field conditions. Materials and methods Panels of cassava genotypes, with non- or late and early flowering response, 10 in each case, were subjected to RLE from dusk to dawn. RLE was further evaluated at low (LL), medium (ML) and high (HL) red light intensities, at ~  ≤ 0.5; 1.0 and 1.5PFD (Photon Flux Density) in µmol m −2  s −1 respectively. Additionally, the effect of a cytokinin and anti-ethylene as plant growth regulators (PGR) and pruning under RLE treatment were examined. Results RLE stimulated earlier flower initiation in all genotypes, by up to 2 months in the late-flowering genotypes. Height and number of nodes at first branching, particularly in the late-flowering genotypes were also reduced, by over 50%. Number and proportion of pistillate flowers more than doubled, while number of fruits and seeds also increased. Number of branching levels during the crop season also increased by about three. Earlier flowering in many genotypes was most elicited at LL to ML intensities. Additive effects on flower numbers were detected between RLE, PGR and pruning applications. PGR and pruning treatments further increased number and proportion of pistillate flowers and fruits. Plants subjected to PGR and pruning, developed bisexual flowers and exhibited feminization of staminate flowers. Pruning at first branching resulted in higher pistillate flower induction than at second branching. Conclusions These results indicate that RLE improves flowering in cassava, and its effectiveness is enhanced when PGR and pruning are applied. Thus, deployment of these technologies in breeding programs could significantly enhance cassava hybridizations and thus cassava breeding efficiency and impact.

Pear trees, though self-pollinating, are self-incompatible and depend on insect pollination—primarily by honey bees. The optimal density of honey bee colonies per unit area in pear orchards remains uncertain, hindering scientific pollination management. This study in Zhao County, Hebei, compared honey bee (Apis mellifea ligustica), artificial, and natural pollination effects on pear yield and fruit size. Honey bee pollination achieved a higher, more stable fruit set (inflorescence fruit set rate was 71.52%), increased yield, and significantly improved fruit size—in transverse diameter (90.96 mm), longitudinal diameter (92.48 mm), and single-fruit weight (407.39 g)—compared with natural pollination. Although the fruit set rates and fruit quality of bee-pollinated pears were not significantly higher than those of artificially pollinated pears, the data still demonstrated the advantages of honey bee pollination. One bee colony (containing ~20,000 honey bees) was found to pollinate approximately 3846.5 m2 of a pear orchard. This provides data-supported guidance for the scientific allocation of pollinating honey bee colonies in future pear orchard pollination practices.

Tissue-cultured (TC) date palms produce no fruit or low yield due to abnormal fruit setting. To improve the yield of TC ‘Berhi’ palms, trees were pollinated using five pollen sources (Gantar, Ghannami, Mazafati, Zahedi, and Jarvis). The experiment was carried out in three replications for two successive years in a randomized complete blocks design. The fruit set, the fruit and seed physical traits at the Khalal stage, bunch weight at the Tamar and Khalal stages, ripeness of Tamar bunch, and the fruit quality at both Khalal and Tamar stages were measured and monitored. Year factor significantly affected the fruit set and the fruit and seed characteristics. Pollen sources affected fruit set and some seed characteristics significantly. Zahedi+Jarvis pollen treatment that induced 50% normal fruit set and the highest ratio of pulp to seed was found superior. It was also a top treatment in Khalal’s bunch weight (3.11 Kg). Zahedi+Gantar treatment was realized superior in Tamar’s bunch weight (6.00 Kg). Ghannami, Jarvis+Ghannami, and Zahedi+Jarvis treatments produced Khalal’s fruits with higher quality indices but Zahedi+Jarvis treatment was superior in fruit quality at the Tamar stage. Overall, the combined application of Zahedi and Jarvis pollens yielded the most desired outcomes.

The occurring temperature increase in crop production areas worldwide is generating conditions of heat stress that negatively affect crop productivity. Tomato ( Solanum lycopersicum ), a major vegetable crop, is highly susceptible to elevated temperatures. Under such conditions, fruit set is dramatically reduced, leading to significant yield losses. Solanum pimpinellifolium , a wild species closely related to the cultivated tomato, was shown to have beneficial attributes under various abiotic stress growth conditions. We have utilized a new population of backcross inbred lines originated from a cross between S. pimpinellifolium and S. lycopersicum , in order to evaluate its potential as a new genetic resource for improvement of reproductive performance of cultivated tomato under heat stress conditions. This population was screened for various heat stress-related traits, under controlled heat stress and non-stress conditions. Our results show that significant variation exists for all the heat stress related traits that were examined and point at individual lines with better reproductive performance under heat stress conditions that share a common introgression from the wild S. pimpinellifolium parent, suggesting several candidate genes as potential drivers of thermotolerance. Thus, our results place this population as a valuable new resource for the discovery of heat stress related genetic loci for the future development of heat stress tolerant tomato cultivars.

Plant hormones are considered to be important mediators of the fruit developmental signal after pollination. The role of phytohormones in tomato (Solanum lycopersicum) fruit set was investigated here. Transcriptome analysis of ovaries was performed using two complementary approaches: cDNA-amplified fragment length polymorphism (AFLP) and microarray analysis. The gene expression profiles obtained suggest that, in addition to auxin and gibberellin, ethylene and abscisic acid (ABA) are involved in regulating fruit set. Before fruit development, many genes involved in biotic and abiotic responses are active in the ovary. In addition, genes involved in ethylene and ABA biosynthesis were strongly expressed, suggesting relatively high ethylene and ABA concentrations before fruit set. Induction of fruit development, either by pollination or by gibberellin application, attenuated expression of all ethylene and ABA biosynthesis and response genes within 24 h. It is proposed that the function of ABA and ethylene in fruit set might be antagonistic to that of auxin and gibberellin in order to keep the ovary in a temporally protected and dormant state; either to protect the ovary tissue or to prevent fruit development before pollination and fertilization occur.

Loquat fruits with a softer texture are susceptible to mechanical injuries and infection by pathogens during transportation and storage. Fruit ripening and softening are intricate processes, characterized by an interplay and coordination among metabolic pathways associated with biological functions. In this study, we aimed to elucidate the variation in the characteristics and potential determinants of cell wall dynamics throughout the developmental stages. Fruit firmness, pectin content, peroxidase and catalase activities in loquat fruit peel as well as pulp of three cultivars viz., ‘Golden Yellow’, ‘Saharanpur Special’ and ‘Tanaka’ at four fruit developmental stages from 60 days after fruit set (DAFS) to 92 DAFS (i.e., 60 DAFS [green stage], 75 DAFS [colour break stage], 85 DAFS [yellow stage] and 92 DAFS [orange stage]) were studied during 2 successive years, i.e., 2022 and 2023. The decrease in the firmness, pectin, peroxidase and catalase activities was positively correlated with the decline in the hardness during the fruit development. The maximum firmness, peroxidase and catalase enzymes during development were observed in cultivar ‘Tanaka’ at 92 DAFS (orange stage). Correlation analysis indicated complex interplay between biochemical components (such as pectin) and oxidoreductase enzymes (such as peroxidase and catalase) in regulating fruit firmness throughout the developmental stages of loquat cultivars. These findings will be helpful in providing systematic information on dynamic regulation of these processes, which is essential for improving fruit quality and developing strategies for enhancing post-harvest storage and transportation of loquat fruits.

Low fruit set in Wurfbainia villosa var. villosa has been a major constraint in its cultivation, with the effective pollination period (EPP) identified as a key factor. In this study, the EPP was assessed for the first time by examining stigma receptivity, style suitability, pollen tube growth rate, and ovule longevity, determined by fluorescence emission microscopy, along with initial fruit set (IFS) determined by sequential hand-pollination of flowers of two cultivars of W. villosa var. villosa under field conditions in Xishuangbanna, South China, in 2022 and 2023. The results showed that the inner surface of the stigma is the receptive region, with receptivity lasting more than three days, as confirmed by pollen adhesion and pollen germination. Style suitability, determined by successful pollen tube entry into the ovule, was maintained for two days; most pollen tubes reached the ovules within one day when stigma receptivity was highest. Ovule longevity persisted for at least three days. The IFS was highest when pollinated at 0–1 days after anthesis (DAA) but dropped sharply to near 0% by 2 DAA. Both EPP estimates, based on its components and IFS, indicated that the EPP is two days, with style suitability being the primary limiting factor.