Higher Percentage Of Fruit Set Research Articles

Impact of Training Techniques and Hybrid Varieties on Tomato Yield in Shade Net House Cultivation

This study investigates the impact of training systems and hybrid selection on the yield of tomato (Solanum Lycopersicon) grown under a shade net house environment. The experiment, conducted at the Hi-Tech Horticulture Unit, Centre of Excellence for Vegetables, Karnal, utilized a Factorial Randomized Block Design with three replications. Two training systems (one-stem and two-stem) and four indeterminate hybrids (STH-39, STH-901, STH-801, and STH-701) were evaluated for their influence on key vegetative and reproductive parameters. Results revealed that the two-stem system significantly improved yield per plant (6.93 kg) and per square meter (15.36 kg) due to increased cluster formation and fruit set percentage. Conversely, the one-stem system promoted larger fruit size, with an average fruit weight of 105.50 g, indicating its suitability for markets valuing larger produce. Hybrid STH-801 exhibited superior performance, recording the highest yield per plant (6.52 kg) and yield per square meter (15.68 kg), along with the greatest number of fruits per cluster (7.75) and highest fruit set percentage (93.17%). Additionally, the STH-39 hybrid produced the largest fruits with an average diameter of 6.30 cm and volume of 157 cc. The findings underscore the importance of selecting appropriate training systems and hybrids to optimize productivity and fruit quality under protected cultivation. This research offers practical insights for growers seeking to enhance profitability through sustainable agricultural practices, particularly during off-season periods under challenging climatic conditions.

Performance of tomato cultivars grafted on root-knot nematode resistant Solanum torvum rootstock for growth and yield parameters

Aim: To study the grafting of tomato cultivars on root-knot nematode resistant Solanum torvum for plant growth, yield parameters and nematode damage under polyhouse conditions. Methodology: Three tomato cultivars viz., Arka Samrat, Saaho and SVTD8323 were grafted on Meloidogyne incognita-resistant S. torvum Sw. (IC618029) by cleft grafting technique. The experiment was conducted in a polyhouse using factorial randomized block design (FRBD) with two factors. The first factor was planting material with grafted and non-grafted tomato cultivars. The second factor was with and without nematode infestation. Observations on plant growth and yield parameters were taken. Results: Grafted and non-grafted tomato cultivars differed significantly in terms of flowering and yield parameters and nematode damage. Under nematode-infested conditions, grafted cultivars yielded significantly more number of flowers per cluster (4.22 to 4.47), flower clusters per plant (11.25 to 11.63), fruits per cluster (3.74 to 4.19), higher percentage of fruit set (89.78 to 94.00) and fruit yield per plant (2,984.6 to 3114.36 g), with less nematode damage (10.60 to 11.53 galls per root system) as compared to non-grafted cultivars (302.53 to 314.33 galls per root system). Interpretation: Tomato grafting with S. torvum rootstock can be utilized in root-knot nematode management, especially in protected cultivation. Key words: Meloidogyne incognita, Nematodes, Rootstock, Tomato grafting, Wild brinjal

Cooler Is Better: The Role of Temperature in the Reproductive Biology of Persian Walnut (Juglans regia L.) Studied in a Hungarian-Bred Cultivar

The aim was to determine the growth of pollen tubes throughout the transmitting tissue and the process of fertilization in open, optimal and over pollination on the 3rd, 6th and 9th day after pollination of pistillate flowers, together with apomixis. The experiment was carried out over 2 years in Lovasberény, Fejér district, Hungary, which differed in temperature conditions. The average number of pollen tubes in the locule of the ovary was significantly higher in 2017 (1.3%) than in 2019 (1%). A higher percentage of fruit set was recorded in 2017 compared to 2019. The percentage of apomictic fruits from variant of unpollination was higher in 2017 (10%) than in 2019 (3.7%). Based on these results it can be concluded that pollen tube growth and post-fertilization processes together with apomixis of cultivar ‘AK’ are better adaptable to lower temperatures. These findings may help us to move walnut production to the north or to higher altitudes, where the climate is more continental.

Effect of Foliar Feeding of Plant Growth Regulator and Nutrients on Phenological Attributes of Guava (Psidium guajava L.) cv Apple Colour

Guava, (Psidium guajava L.), small tropical tree or shrub of the family Myrtaceae, cultivated for its edible fruits. Guava trees are native to tropical America and are grown in tropical and subtropical areas worldwide. Nutrients and PGR play a crucial role in flowering and fruit production and their deficiency can significantly impact the yield, productivity, and quality of fruits. Therefore, keeping these points in view, the present investigation was carried out on a 10-year-old guava plant in a high-density plantation (3x3) at the Fruit Research Station Imaliya, Department of Horticulture, J.N.K.V.V., Jabalpur (M.P.) during the mrig-bahar season of 2022-23. The study employed a Factorial Randomised Block Design (FRBD) with 20 treatment combinations involving Plant Growth Regulators (PGR) like salicylic acid and various nutrients, replicated three times. Results indicated that the combination of salicylic acid (200 ppm) + borax (0.5%) significantly influenced several phenological parameters. This treatment resulted in the earliest flower bud initiation (18.33 days) after foliar application, the highest average number of flower buds per shoot (7.05), minimum days to 50% flowering (33.67 days), maximum average number of flowers per shoot (6.95), the highest fruit set percentage (92.18%), the highest fruit retention percentage (81.23%), and the lowest fruit drop percentage (18.77%). The application of salicylic acid at 200 ppm in conjunction with borax at 0.5% (S2 M4) followed by salicylic acid at 300 ppm with borax at 0.5% (S3 M4) demonstrated exceptional efficacy in significantly optimizing phenological parameters when compared to the control.

Studies in the seed ecology and seedling Phenology of Andrographis paniculata (Brum. f.) Wall. ex Ness in West Bengal, India

Andrographis paniculata (Brum. f.) Wall. ex Nees is an important medicinal plant of tropical Asia and has been used widely for a long time for different clinical ailments. Despite profuse flowering and a high percentage of fruit set,the number of seedlings in the natural population is the bare minimum. Knowledge regarding the seed ecology and seedling phenology of A. paniculata, is needed to formulate conservation strategies for the species. Therefore, a detailed study on seed ecology and seedling phenology has been conducted. During seed ecological studies,seed production, seed-set percentage, seed-ovule ratio, mechanism of seed dispersal, seed structure along with germination status, viability, dormancy and its breaking, and percentage of moisture content loss have been studied. Seeds exhibit some kind of dormancy [germination percentage (GP) = 28.51 ± 0.98, mean germination time (MGT) = 33.07± 0.89 days, and germination index (GI) = 0.73 ± 0.08] which can be effectively overcome through acid scarification using H2SO4 and hot water treatment. The species shows epigealphanerocotylar germination. The hypocotyls exhibit rapid growth, and cotyledons emerged at 7.52±0.27 TARA (Time After Radicle Appearance in days). Seedling is characterised by a thickened, hairy hypocotyl, a distinct collet, a pair of paracotyledons, and three pairs of eophylls in opposite decussate phyllotaxy. The studies on seed ecology and seedling phenology play a significant role in understanding how the shortening of the inception period enhances the germination status, and distinct seedling morphology provides the opportunity to formulate conservation strategies in their wild habitat.

Optimized Protocol for in vitro Pollen Germination in Brinjal (Solanum melongena L.)

Background: Understanding floral and pollen biology is essential for efficient artificial hybridization in hybrid seed production. This knowledge helps ensure proper fertilization of the ovary and optimal fruit and seed set. Selecting suitable pollen parents and preserving pollen for future use allows for better control and optimization of hybridization practices in brinjal breeding programs. To achieve this, a robust protocol for pollen collection and viability testing is necessary to monitor pollen quality in the field and during storage. This information is crucial for maintaining desired characteristics and genetic traits in the resulting hybrid seeds. Methods: This study; aimed at optimizing the pollen germination assessment protocol for brinjal. The step wise modification standard medium composition was done, the optimal growth condition was tested and in vivo predictions were made. So, the study aimed to standardization of media for in vitro pollen germination evaluate and viability in brinjal in ambient as well as cold storage conditions. The pollen germination was tested in vitro as well in vivo, by incubating the pollen grains for 3 hours at 25°C in different concentrations of sucrose, boron and agar media and distilled water at interval of 12 hours. Result: The most favorable germination of fresh pollen was achieved with a treatment consisting of 1% Agar, 12% Sucrose and 300 ppm Boron. Comparing the two storage conditions, pollen stored in the refrigerator exhibited higher in vitro germination percentages compared to ambient storage conditions. The highest in vitro pollen germination and viability percentages were observed in fresh pollen collected within 12 hours (95.00%). As the duration of pollen storage increased in both storage conditions, the in vitro pollen germination decreased. This decline in in vitro pollen germination was reflected in the in vivo fertilization fruit set percentage. The highest fruit set percentage was observed when pollen was stored in the refrigerator (64.52%) and when female flowers were pollinated with pollen stored for less than 12 hours (84.66%).

Effect of pre-flowering sprays of micronutrients on flowering, fruit set, fruit drop and yield of mango cv. Amrapali ​

Being the national fruit of India, mango possess a significant position in its history, tradition culture and economy. This delicious and nutritious fruit contains considerable amounts of vitamins, minerals, and antioxidants in abundance. The plant flowers in panicle at the end of winter and fruit drop is a common problem which is manifested due to several causes and micronutrient deficiency is one of major cause. The present study was conducted at the instructional farm of Institute of Agriculture, Visva Bharati, Sriniketan which comes under humid sub-tropical region of West Bengal, India during the year 2020 and 2021 to study the effect of pre-flowering sprays of zinc and boron on panicle emergence and panicle growth of mango cv. Amrapali. The experiment comprised of 9 treatment combinations of pre flowering sprays of zinc sulphate (ZnSO4, 7H2O) and borax (Na2B4O7, 10H2O) replicated 3 times as T1: Control (distilled water), T2: ZnSO4 @ 0.5%, T3: ZnSO4 @ 1.0%, T4: Borax @ 0.5%, T5: Borax @ 1.0%, T6: ZnSO4 @ 0.5% + Borax @ 0.5%, T7: ZnSO4 @ 0.5% + Borax @1.0%, T8: ZnSO4 @ 1.0% + Borax @ 0.5% and T9: ZnSO4 @ 1.0% + Borax @ 1.0%in Randomized Block Design (RBD). Highest number of total flowers and hermaphrodite flowers per panicle were recorded under ZnSO4 @ 1.0% + Borax @ 1.0% spray (T9). Apart from these, higher percentage of fruit set and lower fruit drop in all the stages have also been observed ZnSO4 @ 1.0% with Borax @ 1.0% treatment (T9). Same treatment also exhibited maximum yield in both the years. Thus, foliar application of ZnSO4 @ 1.0% and Borax @ 1.0% can be used at pre-flowering stage in mango (cv. Amrapali) for good flowering, high fruit set and less fruit drop.

Influence of Gibberellic Acid and Mulch Materials on Yield and Biochemical Attributes of Strawberry (Fragaria × ananassa) cv. Festival

One of the most important factors in strawberry (Fragaria × ananassa) cv. Festival production for achieving higher yields is the availability of strawberries with better quality. The experiment was carried out during the period from November 2020 to March 2021 to find out the responses of gibberellic acid (GA3) and mulch materials on biochemical and quality attributes related to strawberry yield characteristics. The experiment consisted of two treatments including different mulch materials: black polythene, white polythene, sawdust, and control (no mulch); and GA3 (0 and 200 mg/L) were studied. Various quality parameters, namely total soluble solids (TSS), pH, titratable acidity, ascorbic acid, total sugar, phenolic, and anthocyanin content of the strawberries were determined. The results observed in the GA3-treated plants showed more significant results than the plants not treated with GA3. Among the mulch materials, sawdust performed better than the other mulch materials in terms of yield, biochemical, and quality attributes. The highest fruit set percentage (89) and fruit yield (18.70 t/ha) were obtained from the GA3 and sawdust mulch treatments. GA3 and sawdust mulch performed best in terms of quality parameters including TSS, pH, ascorbic acid, total sugar, phenolic, and anthocyanin content. Accordingly, sawdust and GA3 are more responsive to strawberry plant quality parameters. These findings provide practical insights for sustainable strawberry cultivation practices, contributing to increased fruit availability and improved nutritional value for consumers.

Fruit Set dan Daya Simpan Buah Tanaman Cabai Rawit (Capsicum frutescens L.) Akibat Pemberian Paklobutrazol dan Pupuk Organik Cair Buah Pisang

Increasing the productivity of cayenne pepper (Capsicum frutescens L.) can be done through the use of growth regulators, namely paclobutrazol and liquid organic fertilizer. Treatment of paclobutrazol concentrations and doses of liquid organic fertilizer derived from banana fruit waste is expected to increase the fruit set and storability of the resulting cayenne pepper. The purpose of this study was to determine the best concentration of paclobutrazol and POC banana fruit to increase the fruit set of cayenne pepper, and to determine the best concentration of paclobutrazol to produce cayenne pepper with a more resistant shelf life. The research method used was using a Split Plot Design with the main plot being the dosage of liquid organic fertilizer for bananas, which consisted of NPK 40 g/plant (control), 300 ml/plant POC banana, 400 ml/plant and 500 ml/plant POC bananas. While the concentration of paclobutrazol as a sub-plot, which consisted of 0 ppm/without paclobutrazol (control), 100, 150 and 200 ppm. The results showed that there was a significant interaction between the combination treatment concentrations of paclobutrazol and the dosage of liquid organic fertilizer for bananas in the observed parameter of fruit set percentage. A higher percentage of fruit set was obtained from the combination treatment of 150 ppm paclobutrazol concentration with a dose of 300 ml/plant of banana liquid organic fertilizer. The concentration of paclobutrazol had a significant effect on the storability of cayenne pepper. Cayenne pepper that more resistant to storage were obtained from treatment with a concentration of 150 ppm paclobutrazol.

Increasing off-season snake fruit (Salacca zalacca) yield by preventing fruit set failure with different exogenous auxin spray

Snake fruit blooms every three months, but only one to two of the flowering seasons result in fruit production. Failure of fruit set causes the fruit harvest seasonally. Therefore, the aim of this research was to increase off-season production by preventing the failure of fruit set with various exogenous auxin spray. The research was conducted in the snake fruit orchard at Bebandem Sub-District, Karangasem Regency, Bali Province, Indonesia, from February to November 2019. The experiment was designed as a nested factorial with a randomized block design. The treatment consisted of three types of auxin with a specific concentration for each, IAA at 0, 25, 50 and 75 ppm, IBA at 0, 50, 100 and 150 ppm, and NAA at 0, 50, 100 and 150 ppm. The IAA, IBA, and NAA were sprayed on the flowers and leaves 3 times in March, April, and May. The results showed the highest percentage of fruit set, fruit weight per tree, and weight per fruit obtained with IAA treatment were 59.80 %, 2,612.91 g, and 91.06 g, respectively. These results were not statistically different to those of the IBA and NAA. Furthermore, the IAA concentration of 25, 50, and 75 ppm produced a significantly higher percentage of fruit set compared with the control. The increased fruit set in the IAA, IBA and NAA treatments resulted in better yield than the control. The novelty of this result is that spraying snake fruit with IAA, IBA and NAA can prevent the failure of the fruit set. Therefore, IAA, IBA, and NAA are recommended to be applied to increase off-season fruit production of snake fruit.

Effect of pollination time, the hour of daytime, pollen storage temperature and duration on pollen viability, germinability, and fruit set of date palm (Phoenix dactylifera L.) cv "Deglet Nour"

Success artificial pollination with viable pollen is crucial process in the production chain of date palms. This study evaluated the impact of pollen storage temperature and duration, pollination time following spathe cracking, and the hour of daytime on pollen viability, germinability, fruit set and yield of 'Deglet Nour' date palm cultivar. In in vitro tests, fresh pollen showed the maximum viability (96.3%) and germination (85%) but it decreased thereafter upon the storage temperature (28, 4 and −30 °C) and duration (3, 6, 9 and 12 months). In this respect, pollen stored at −30 °C retained highest viability and germinability followed by those stored at 4 and then at 28 °C. In filed experiments, fruit set was 85, 75, 65, and 45% with pollination using fresh pollen, or pollen stored at −30, 4 and 28 °C, respectively. Fruit set was 95%, 75%, and less than 50%, for pollination performed on the same day of spathe cracking, 6 and 12 days later, respectively. The highest fruit set percentage and yield/bunch were obtained with pollination performed between 12.0 pm and 15.0 pm in contrast to 8.0–11.0 am or 16.0–17.0.

Induction of flowering and improvement of fruit yield and quality in pomegranate (Punica granatum) cv. Bhagwa by various plant growth regulators

The effect of different plant growth regulators on flowering, fruiting, yield, and quality of pomegranate (Punica granatum L.) cv. Bhagwa was studied in a field trial at ICAR - Indian Institute of Horticultural Research (IIHR), Bengaluru, during two seasons, namely ambe bahar (January–February) 2016 and hastha bahar (September–October) 2016-17. Nitrobenzene (NB) 1.0, 1.5, and 2.0 ml plant-1, Cycocel (CCC) 500, 1000, and 1500 ppm plant-1, Uracil 25 and 50 ppm plant-1, CCC 1000 ppm + Uracil 25 ppm plant-1, CCC 1500 ppm + Uracil 50 ppm plant-1, and Control were among the eleven treatments studied. The application of uracil 50 ppm plant-1 resulted in a higher number of hermaphrodite flowers plant-1 (264.7), number of fruits plant-1 (154.0), and fruit yield (27.1 kg/plant). Fruit weight (197.6 g), fruit length (6.64 cm), total aril weight (113.63 g), 100 aril weight (27.18 g), fruit juice weight (101.94 g), TSS content (19.96 OB), fruit anthocyanin content (6.46 mg 100 g) and low titrable acidity (0.41 percent) were recorded when CCC 1000 ppm + Uracil 25 ppm plant-1 was applied. During ambe bahar, the highest fruit width (6.90 cm) and volume (162.7 ml) were observed with CCC 1000 ppm and 1500 ppm plant-1, respectively. During hastha bahar, CCC 1500 ppm plant-1 resulted in a higher number of hermaphrodite flowers (287.8), the highest percentage of fruit set (86.10), the highest number of fruits plant-1 (156.66), the highest fruit yield (54.53 kg plant-1), the highest fruit weight (348.32 g), the longest fruit length (8.53 cm), and the largest fruit volume (8.53 cm) (33.93 ml), total aril weight (224.01 g), 100 aril weight (35.09 g), fruit juice weight (119.40 g) and TSS content (16.00 OB). A foliar spray of nitrobenzene 1.5 ml plant-1 compounded the high fruit anthocyanin content (6.47 mg 100g-1). As a result of the research, it can be concluded that CCC 1000 ppm + Uracil 25 ppm plant-1and CCC 1500 ppm plant-1were the most effective treatments for improving floral characters, fruiting, yield, and quality in pomegranate cv. Bhagwa during both seasons.

Pollination and hybridisation systems in genus Ribes L. (Grossulariaceae)

Currants are important berry crops cultivated for medicinal purposes. Most currant cultivars are crossings between Ribes nigrum varieties, while many Ribes species are not used in hybridisation. Recent research on Ribes crossbreeding is scarce. Hybridisation of wild species can improve reproductive success and the taste of fruit. However, hybrids of certain currant species cannot produce fully formed berries. Crossbreeding of currant species was performed in Northwest Russia (Saint Petersburg Botanical Garden). The research included both introduced (R. sachalinense, R. sanguineum, R. rubrum, R. hispidulum, R. mandschuricum, R. spicatum, R. latifolium) and native species (R. aureum, R. alpinum, R. nigrum). The research aimed to identify the hybridisation system, pollination mechanisms and hybrids with the highest percentage of fruit and seed set. Pollen fertility and viability were assessed. Pollen is fertile (acetocarmin staining: 80.3% for R. alpinum and 96.0% for R. mandschuricum); germination is active on nutrient medium and in situ, especially in R. sachalinense, R. aureum and R. spicatum (54.2–41.8%). Pollen germination can be irregular. Flowers were castrated before pollination. Optimal hybrids with a high percentage of fruit set were identified: R. alpinum x R. mandschuricum, R. alpinum x R. aureum, R. sachalinense x R. sanguineum, R. rubrum, R. hispidulum.

Relationship of severity pruning and weather variables on quality fruit production of ber (Ziziphus mauritiana L. cv. Sanaur-2)

Pruning had a vital role on the quality of fruit production in ber fruit crop under lower Shiwaliks of Punjab. The severity of pruning intensity significantly influenced the tree vegetative growth parameters and flowering behaviour of ber cv. Sanaur-2 viz. number of emerged shoots per branch, shoot length and girth of primary shoot. A significant higher percentage of fruit set, fruit retention, higher percentage of ‘A’ grade fruits and other fruit quality parameters viz., fruit weight, TSS, acidity, vitamin C, total sugars was recorded significantly higher in pruning treatment by removal 50 per cent vegetative growth over other treatments. Powdery mildew incidence steadily increased from standard meteorological weeks (SMW) 36 - 39 to 40 - 43 and then decreased under different pruning treatments. The severity of pruning reduces the incidence of powdery mildew. The meteorological knowledge on various weather variables at 3 - 4 weeks to actual incidence also can be effectively used to check the spread and severity of the disease.

Pod set and Pollen Viability Studies in Yard Long Bean (Vigna unguiculata sub sp. sesquipedalis)

A study was conducted in a yard long bean (Vigna unguiculata sup/ssp. sesquipedalis) hybrid VS 50 (Kakkamoola Local) x VS 26 (Vellayani Jyothika) to assess the percentage fruit set at two time intervals and to identify the best time interval for pollination in yard long bean hybrids. Hand pollination was done using VS 50 as female parent and VS 26 as male parent for seven consecutive days at two time intervals, 6.30 – 7.30 am and 7.30 – 8.30 am. Higher percentage of fruit set (36.8 %) was observed between 6:30 – 7:30 a.m. as compared to the time interval 7:30 – 8:30 am. (23.8%). Pollen viability was determined for the parents VS 50 (Kakkamoola Local) and VS 26 (Vellayani Jyothika) at 6.30, 7.30 and 8.30 am. Highest pollen viability for both the parents VS 50 and VS 26 was observed during 7.30 am. The present study shows that the best time interval for crossing in yard long bean is 6.30- 7.30 a.m.

Pod set and Pollen Viability Studies in Yard Long Bean (Vigna unguiculata sub sp. sesquipedalis)

A study was conducted in a yard long bean (Vigna unguiculata sup/ssp. sesquipedalis) hybrid VS 50 (Kakkamoola Local) x VS 26 (Vellayani Jyothika) to assess the percentage fruit set at two time intervals and to identify the best time interval for pollination in yard long bean hybrids. Hand pollination was done using VS 50 as female parent and VS 26 as male parent for seven consecutive days at two time intervals, 6.30 – 7.30 am and 7.30 – 8.30 am. Higher percentage of fruit set (36.8 %) was observed between 6:30 – 7:30 a.m. as compared to the time interval 7:30 – 8:30 am. (23.8%). Pollen viability was determined for the parents VS 50 (Kakkamoola Local) and VS 26 (Vellayani Jyothika) at 6.30, 7.30 and 8.30 am. Highest pollen viability for both the parents VS 50 and VS 26 was observed during 7.30 am. The present study shows that the best time interval for crossing in yard long bean is 6.30- 7.30 a.m.

Analysis the effects of pollen grain sources on the fruits set and their characteristics of ‘Clementine’ mandarin using microscopic and molecular approaches

‘Clementine’ is one of the most important cultivars of mandarin that always has problems with fertilization and fruit set because of its self-incompatibility. Therefore, for the commercial fruit production, suitable and compatible pollen is required. To determine the best pollen source, ‘Clementine’ flowers were subjected to the different pollen grains including sweet lemon, Lisbon lemon, grapefruit, sour orange, as well as self-pollination and open pollination. Compatibility and incompatibility tests were carried out using controlled pollination method and microscopic study of pollen tube growth. Molecular markers were used to study the genetic relationships of the species and assess the role of genetic similarity on the fruits set and their attributes. The results of the microscopic study indicated that ‘Clementine’ mandarin is a self-incompatible cultivar but it is compatible with all the cultivars used in the experiment. Clementine fruit characteristics significantly influenced by pollen grain sources. The results of controlled pollination showed that the highest percentage of fruit set was obtained from flowers pollinated with sweet lemon pollen (73.75%) followed by Lisbon lemon pollen (69.25%) while the lowest fruit set was obtained from the self-pollinated flowers (11.75%). The highest and the lowest hale seeds were obtained from the flowers pollinated by Lisbon lemon pollen (12.22%) and self-pollinated ones (no viable seed), respectively. High correlation was observed between some of the studied characters that would be useful for selection purposes in the breeding programs. Results of microscopic evaluation of pollen grain tubes revealed that among the studied pollen grains, sour orange pollens were the most successful for penetration to the basal portion of style and into ovary of ‘Clementine’ mandarin. Assessment of genetic relationship among different Citrus species revealed that sour orange was the most similar species with ‘Clementine’ mandarin. High positive correlation was observed between genetic similarities of pollen sources at DNA level with the pollen grain sprouting and penetration to the different parts of style and ovary as well as seed formation percentages. Based on the studied fruit characteristics, grapefruit and Lisbon lemon pollens are suggested as the suitable pollinators for improving the qualitative and quantitative characteristics of ‘Clementine’ mandarin fruit.

Increased percentage of fruit set of F1 hybrid of Capsicum chinense during high-temperature period

Low percentage of fruit set in fruit vegetables cultivated in greenhouses, such as tomato (Solanum lycopersicum), eggplant (S. melongena), and capsicum (Capsicum), in high-temperature seasons has been reported as one of the biggest problems in commercial vegetable production. In this study, C. chinense ‘Sy-2’ and ‘No. 3686’ were cultivated in greenhouses for a year. Remarkably low percentages of fruit set (3.2% and 0%, respectively) were obtained in the high-temperature season (40 °C/25 °C: day/night). However, the percentage of fruit set was recovered with the decrease in temperature in autumn and winter (30 °C/20 °C). On the other hand, in F1 (‘Sy-2’ × ‘No. 3686’), the percentage of fruit set was 40.8% even in the high-temperature season. On in vitro pollen germination test, the pollen of F1 was found to have a higher germination rate than that of ‘Sy-2’ or ‘No. 3686’ during the high-temperature season. After ‘Sy-2’ was cross-pollinated with ‘Sy-2’ and ‘No. 3686’ pollen, percentages of fruit set were 23.3% and 0%, respectively. It is noteworthy that the cross-pollination of ‘Sy-2’ with F1 pollen resulted in a considerably higher percentage of fruit set (73.3%). When F1 was self-pollinated, the percentage of fruit set (56.7%) was higher than that after when cross-pollinated with ‘Sy-2’ or ‘No. 3686’ pollen. Interestingly, no fruit set was obtained when ‘No. 3686’ was cross-pollinated with ‘Sy-2’, ‘No. 3686’, or F1 pollen. The results for ‘No. 3686’ indicated that not only does the male factor affect pollen germination ability but also unknown female factors are involved in reducing the percentage of fruit set of C. chinense under the high-temperature season. A significant increase in the percentage of fruit set in the high-temperature season was also observed in the reciprocal cross of F1, ‘No. 3686’ × ‘Sy-2’. Furthermore, 10 plants of (‘No. 3686’ × ‘Sy-2’) × ‘Sy-2’ and 31 plants of ‘Sy-2’ × (‘No. 3686’ × ‘Sy-2’) were cultivated in a greenhouse, but no difference was found in the percentage of fruit set between these two combinations. Therefore, our findings suggest that cytoplasmic factor(s) does not influence the percentage of fruit set.

The effect of polyamines and SICS on the compatibility, fertility and yield indices of apple cv. Golden Delicious

The most critical problems of temperate fruit trees are poor fruit set and low yield. To solve the problem, some major chemical compounds such as polyamines and SICS (self-incompatibility control substance, Mn+B) can be used. Popular polyamines including Putrescine (0.1 and 0.25 mM), both Spermine and Spermidine (0.05 and 0.25 mM), and SICS (1 and 2 mg L-1) were used alone or with cotton coverage bags to cover branches in order to investigate self-incompatibility in Malus domestica. Results showed that Spermidine (0.25 mM) led to higher yields in comparison with that of the control. SICS (2 mg L-1), also, demonstrated the highest yield compared with that of the control. At June fruit set, treatment with Spermidine (0.25 mM) led to the highest percentage of fruit set and also the highest index of self-incompatibility and percentage of final fruit set among treatments.

Effect of androecious genotypes as pollinizers on ‘Soshu’ persimmon fruit quality

Several androecious germplasms bearing only staminate flowers were collected from Dabie Mountains located in central China. The effect of those genotypes as pollen sources on leading commercial cultivar fruit setting and quality has not been elucidated yet. The fruit characteristics of Japanese PCNA cultivar 'Soshu' were assessed after pollination with 'Male 1', 'Male 3', 'Male 8' and 'Zenjimaru'. The blossom period of 'Male 8' and two other androecious genotypes lasted respectively for 2 weeks and 10 days longer than 'Zenjimaru', overlapping the leading cultivar blooming. Pollen germination on 'Soshu' stigma was analysed through in vivo and in vitro microscope observation. The highest percentage of fruit set and average fruit weight were obtained by pollinating with 'Male 8'. The average seed number per fruit varied from 2 to 4. Fruit juice and skin color were also affected by the pollen donors. In addition, differences in flesh firmness, tannin content, Vc content, soluble solids content, titratable acid contented depended on treatments. SPSS and PCA analysis of the pollen donors revealed that 'Male 8' with stable androecy improved the fruit characteristics. The fruit yield and internal quality of 'Soshu' × 'Male 8' exceeded the results obtained from other pollen donors and open-pollination, although fruit quality could also be enhanced with other pollen sources. Thus, 'Male 8' must be considered as an important potential genetic resource as pollen donor for persimmon orchard production.