Good Fruit Set Research Articles

Crossability of miniature rose and quantitative and qualitative traits in hybrids.

Potted miniature roses are popular indoor ornamental plants. Due to consumer demands, different varieties are introduced to the market every year. The most widely used method for the development of potted miniatures is cross breeding. Six divergent popular pot miniature roses as female parents and Rosa centifolia and Black Baccara as male parents as well as 190 of their F1 hybrids were studied to determine the extent of crossability and the heterosis effects for several quantitative and qualitative traits for determining miniature rose breeding potential. The percentage of pollen viability and the pollen germination rate differed between 48.61% and 61.27% and between 23.26% and 32.19%, respectively. All cultivars exhibited a strong correlation between the fruit set, the weight of fruit, the total set, the weight of seed, the number of seeds per fruit, and the seed germination rate. The cultivar Rosa White Star as a female parent exhibited a good fruit set and crossing success, whereas Juanita Kordana showed a poor crossing success rate. The maximum setting after the crossing was that of Rosa White Star × R. centifolia comprising 75% of fruits, 132 total seeds, and seed weight of 0.68 g. The highest number of seeds per fruit (12.63) was obtained from Rosa Bling Love Star × R. centifolia, and the Red Romance × Black Baccara had the maximum germination of seed rate (48%). The potential for heterobeltiosis and heterosis varied and exhibited a contrasting performance for various qualitative and quantitative traits between F1 progenies. The parents and F1 hybrids were sorted into three major groups by cluster analysis based on the phenotypic variation.

Description of buckwheat cultivars from Belarus and Ukraine in the environments of Leningrad Province

Background. Buckwheat is an extremely valuable groat crop in demand both in Russia and abroad. The buckwheat collection held by VIR is the largest in the world. Studying and systematizing knowledge about the conserved diversity of the genus Fagopyrum Mill. representatives cannot be efficient without switching to the use of the most detailed descriptors containing plant characters least dependent on differences in growing conditions.Materials and methods. Seventeen buckwheat cultivars from Ukraine and Belarus and two references from Russia were studied in Leningrad Province. The methodological basis of the study included the IPGRI buckwheat descriptors and personal recommendations of N. V. Fesenko. Statistical data processing was performed according to P. F. Rokitsky.Results. The cultivars formed their typical plant habitus and demonstrated good fruit setting − an average score was 3.3–4.9 out of five. The determinant stem growth was observed in 10 cultivars. The stem developed 2.7−6.7 generative nodes and 4–6 vegetative ones, while 1.9–4.7 generative and 0.8−2.3 vegetative nodes were formed on the two upper branches.Conclusion. The study confirmed that medium-ripening buckwheat can be grown in Leningrad Province. The modal value of the number of vegetative nodes for the studied cultivars was 4−5, which is an indicator of intermediate ripening. The results of studying the metamerism of the stem and the two upper branches, expressed by modal values, were recorded in the “agricultural fitness” passport for the tested cultivars as follows: determinant stem; branching zone 4+1+2; fruit-forming zone 3+3+3; average score of fruit formation 4.8. The presented data format most fully characterizes a cultivar in terms of the potential of its earliness and productivity. Depending on the task, indicators for the main stem or for the two upper branches can be used. Recording values in the form of a formula is convenient and does not imply any other meanings.

Influence of foliar spray with some calcium sources on flowering, fruit set, yield and fruit quality of olive Kalmata and Manzanillo cultivars under salt stress

BackgroundThis work was carried out through 2017 and 2018 seasons on Kalmata and Manzanillo olive cultivars. Trees were 15 years old, grown in sandy soil and planted at 5 × 5 m apart irrigated with saline water through drip irrigation system. This investigation aimed to improve flowering, fruit set, yield and fruit quality of the tow olive cultivars. Trees were sprayed with calcium at 0.5% as calcium chloride (21% Ca) and chelated calcium.ResultsThe results revealed that there were significant differences with calcium source treatment regarding number of inflorescences/shoot, no. of total flowers/inflorescences, sex expression, initial fruit set, final fruit set (%) and yield/kg (tree) and decreasing fruit drop (%) of olive oil Kalmata and Manzanillo cultivars compared with unsprayed in both seasons.ConclusionsResults proved that olive trees sprayed at the end of December with 0.5% calcium as chelated calcium was the promising treatment for good flowering, fruit set, yield and fruit quality.

STUDIES ON COMPATIBILITY, FRUIT SET AND FRUIT QUALITY BY DIFFERENT POLLINATORS IN ANNA APPLE CULTIVAR

The apple (Malus domestica) is a member of the Rosaceae family. It is older than the rose in cultivation and is often referred to as the prince of the rose family. Pollen grains of Dorsett Golden, E25 and Ein Shemer were used to investigate their compatibility and incompatibility with Anna cultivar under the Egyptian climatic conditions during two successive experimental seasons of 2016 and 2017. The fluorescence microscope was used to determine the degree of pollen tube growth in style tissue after specific pollination treatments. Degree of self and cross compatibility and or incompatibility were determined, initial, and final fruit set percentage were calculated. Pollination treatments revealed that, pollens of the four apple cultivars exhibited high rate of the viability after 24 hr. in T.T.C test. Growth of pollen tube of the tested cultivars exhibited different pattern of compatibility, the pollen tubes of Dorsett Golden and Ein Shemer cultivars showed different levels of cross-compatibility when fertilized in Anna style tissue. The pollen tube of E25 cultivar grew slowly with heavy deposition of calluses along to the tube where its growth stopped in the lower part of Anna style four days after pollination. Therefore, they need pollinizer cultivars as for good fruit set. On the other hand, Anna self-pollination seemed to be self-incompatible and recorded lowest initial of fruit set percentage in the first and second seasons. The combinations of Anna × Dorsett Golden exhibited maximum percentage of initial and final fruit set in the two seasons followed by Ein Shemer pollens in both seasons. Insignificant differences were noted in fruit weight and fruit volume among all crosses. The highest acidity was found in hybrid Anna × Dorsett Golden in except in the first season TSS values of these crosses were not high and ranged between 11.83 % and 12.83 %.

Evaluation of pollen storage strategies in Cucurbita pepo L.

Male flower shortage is a major reason of insufficient pollination in zucchini (Cucurbita pepo L.), leading to pointy fruits that rot quickly in the post-harvest phase. Harvesting pollen grains early in the season, when male flowers are abundant, followed by storage and subsequent manual pollination, could be a solution, provided that high pollen viability is maintained. Therefore, insight in parameters affecting pollen viability during anthesis and under storage are needed to advice growers on the most successful pollination strategy. Pollen viability was determined using Fluorescein Diacetate (FDA) and digital image analysis performed with Image J. Under practice conditions, viability started to diminish three hours after anthesis. At flower closing, only 60% of pollen grains remained viable and the next morning no more than 10%. In order to assess the impact of storage on pollen viability, pollen grains were subjected to different relative humidities and storage times. Stored at 20°C and 80% RH or lower for four hours, at least 90% of the pollen turned out to be non-viable. At 20°C and 90%, RH pollen viability remained above 50% for eight hours. When female flowers were pollinated with stored pollen (five days or longer), none of the fruits set sufficiently to be marketable, while fresh harvested pollen resulted in 90% marketable fruits. Therefore, pollen should be harvested and applied on the stigma within three hours after anthesis in order to ensure good fruit setting. Pollen could not be stored longer than eight hours without severe loss of viability or pollinating capacity.

Effect of calcium, boron and sorbitol on fruit set, yield and quality of mango (Mangifera indica L.) cv. langra.

Low fruit setting and heavy fruit drop in cv. Langra is a serious problem for mango growers despite the profuse flowering, good fruit setting. Some chemicals like Calcium nitrate, Boric and Sorbitol are able to minimize the loss. The experiment was conducted during the two successive seasons in the years 2012 & 2013 on mango (Mangifera indica L.) cv. Langra with treatments T1-( Calcium nitrate @0.06%), T2-(Boric acid @0.02%), T3-(Sorbitol @2.0%) T4-(Calcium nitrate @ 0.06% + Boric acid @ 0.02%), T5-(Calcium nitrate @ 0.06% + Sorbitol @ 2.0%), T6-(Boric acid @ 0.02% + Sorbitol @ 2.0%) and T7-(Control) with four replications to study on fruit set, yield and quality. The pooled data for the year 2012 and 2013 indicated that the foliar spray of Boric acid @ 0.02% significantly performed better result in regards to highest pulp (78.60%), TSS (19.080Brix), total sugar (11.57%), reducing sugar (2.68%), non-reducing sugar (8.89%), ascorbic acid (33.76mg/100gfw) and carotenoids (8.62mg/100gfw) with lowest value peel (7.45%), stone (13.86%) and acidity (0.30%). The combination effect of Calcium nitrate @ 0.06% + Boric acid @ 0.02% significantly proves better in respect of minimum fruit drop percent (91.19%), whereas; maximum in control (97.35%) as well as in terms of increasing fruit set and yield (138.43kg/tree) of mango cv. Langra.

Foraging behavior of stingless bee (Geniotrigona thoracica and Heterotrigona itama) on star fruit trees (Averrhoa carambola L.)

Star fruit produce flowers and fruits nearly the whole year round and it require cross- pollination for good fruit set and yields. An inadequate pollination rate is one of the factor that contributes to low yield. One of the effective way of increasing the pollination rate is by having insect pollinators such stingless bees in the star fruit farm. Malaysia is rich with native pollinator such as stingless bee, but there still lack of study related on their foraging behaviour. Therefore, the objectives were to study the foraging behaviour of Geniotrigona thoracica and Heterotrigona itama on star fruit trees. The colonies of G. thoracica and H.itama were selected for observation of activity foraging of stingless bee. Foraging bees was enumerated by using a manual tally counter to determine the number of individuals that flew out and into their hive within a 10 minute period each hour for each colonies. Then 10 of foragers’ G. thoracica and H.itama were selected randomly and marked using insect colouring on their thorax The period for each flower that visited by G. thoracica and H.itama was recorded by using stopwatch. The number offlower visited by G. thoracica and H.itama also recorded in 3 minutes. Result showed the peak time foraging activity of both stingless bees were in between 8.00am until 10.00am The foraging activity for each hours showed there was not significant differences, p > 0.05. Then the highest number flower visited by G.thoracica in 3 minute is 31 flowers while the lowest number flower visited in 3 minute is 7 flowers. However, for H.itama the highest number visited flowers are 27 and lowest number visited flowers are 8, for the longest average visited period for each flower is 14.76 seconds and the shortest period is 3.57 seconds. Meanwhile for G.thoracica longest average visited period for each flower is 12.88 seconds and the shortest average visited period for each flower is 2.72 seconds. In conclusion, this experiment showed that stingless bees have the characteristic for effective pollinator and have the potential to be used as a pollinator for star fruit trees. However, temperature, humidity and weather gave big influence on the foraging activity of stingless bees on star fruit plant.

Reproductive Biology and Flowering of Feijoa (Acca sellowiana (Berg) Burret) in Areas of Marginal Occurrence

Studies of feijoa adaptability in different locations, with specific weather conditions can be useful for the cultivation of the species. The objective of this work was to study aspects of reproductive biology (pollen viability and fruit set under different methods of pollination) and flowering phenology of feijoa in regions of marginal species occurrence. Progenies of five different crosses were evaluated in 2011 in Pato Branco and Dois Vizinhos, Paraná, Brazil. Effective fruit set was low with manual self-pollination and open pollination, but was higher with manual cross-pollination, demonstrating a lack of pollinators or even self-incompatibility in some progenies. For both sites, pollen viability was extremely low and atypical for the species. The flowering period of feijoa started earlier and was extended in these marginal regions. Manual pollination is required for a good fruit set.

Fertilization Biology Of Ancient Grape 'Ekşi Kara (Vitis Vinifera L.)

In some institutions in Turkey, grape breeding programs such as hybridization breeding between superior genotypes of Vitis vinifera L. varieties or clonal selection of local genotypes are carried out. Antique and autochthone grape varieties are grown since ancient times in the 'Eksi Kara' ( Vitis vinifera L.), Konya-Karaman provinces and middle Taurus Mountains. Economic value is high in the production area. Well adapted in region. Indispensable in location than many other varieties. It is also promising for similar ecologies. The development requirements of the this very productive variety has been identified as a need. The flower type of the variety is functional female. A pollinator is a requirement for a good fruit set. Another ancient and autochthone grape variety, 'Gok Uzum', is used as a pollen source in the region. Clusters and berry sizes in the 'Eksi Kara' variety in the producer vineyards are closely related to hens and chicken berry development percentage, berry growth, weather conditions (precipitation) during flowering and / or pollination period due to the honey bee activity. This research was carried out under the conditions of the producer vineyards in which selected in the head clone candidates were identified by the 'Eksi Kara' grape variety clone selection project of the Selcuk University Faculty of Agriculture, Department of Horticulture and the laboratory conditions. Fertilization biology of 220 selected head clone candidates were examined. The purpose of the study was to question the existence of self-fertile clones among the head clone candidates. For this purpose, the clone head candidates were self-pollinated in covered clusters, freely pollinated with ‘Gok Uzum’ grape variety and pollens were tested for viability, pollen germination and tube growth of the germinated pollens. All of the head clone candidates did not have any seeded fruit set in the covered flower clusters. Pollen grains were alive in different percentage but in laboratory conditions in all of the tested pollens were not germinate practically (less than 3%). A self-fertile clone candidate has not been identified. Honey bees and some other pollinator insects were the main elements of pollen transport from 'Gok Uzum' to ‘Eksi Kara’. The development of ampelographic and genetic databases will greatly contribute to genetic stocks that have not yet been evaluated in culturally diverse cultures or collections throughout the country, so that the correct identification of genotypes in general will be increased.

Pollen-pistil interaction influence on the fruit set of sweet cherry

Pollination success and final fruit set of sweet cherry depends on self- and cross- (in)compatibility relations among cultivars in orchard. The objective of this study was to determine the compatibility relationships and to select pollenizers for the most important Croatian sweet cherry cultivars, ‘Gomilička’ and ‘Stonska’. Phenological observations, pollen germination, pollen tube growth and fruit set were assessed following self- and cross-pollination treatments in two flowering seasons. In general, we found overlap of flowering periods of all cultivars included in the study, but low synchronization was observed for the full-bloom period among traditional cultivars, particularly ‘Stonska’ (early cultivar) and ‘Tugarka’ (late cultivar). There was a significant difference in fruit set among the type of pollinations and pollen donors. ‘Gomilička’ and ‘Stonska’ are self-incompatible, and cross-pollination is necessary for good fruit set. According to the overlap in flowering time and fertilization level in ‘Gomilička’, cross-pollination with ‘Garnet’, ‘Isabella’ and ‘Starking Hardy Giant’ was more effective than that of the traditionally grown cultivars ‘Stonska’ and ‘Tugarka’, and introduction of these cultivars as pollenizers is a good choice that can provide regular and abundant fruit set. Despite the different S-allele combinations of traditional cultivars, overlap in flowering time with some of the introduced cultivars, and favourable climatic conditions, we found also significant effects of pollen-pistil interactions in the style and ovary on the dynamics of pollen tube growth and final fruit set. Inter-incompatibility reactions between cultivars were not observed.

Ehretia pubescens Benth. with differential germinability patterns due to climate change

Climate change may influence the composition of plant communities by affecting the reproduction, growth, establishment and local extinction of plant species. Predicting the effect of climate change may provide insight into the impact and relationship between weather pattern and flowering phenology in long term studies. Pollen viability is one important factor of reproduction. Pollen viability is essential for a good fruit set. The study is undertaken to evaluate the influence of temperature and rainfall fluctuation pattern on floral phenology and pollen viability in the restricted distribution of the plant Ehretia pubescens Benth. Field observation on floral phenology has revealed changes occurring in the pollen viability with the change of temperature and rainfall. The plants show drought resistant; however, it is observed that it blooms immediately after the rainfall. Change in the rainfall pattern results in change in flowering pattern. On the natural habitat fruit set is a good indicating of good germinability of pollen grain in vivo. In vitro pollen germinability is less efficient for this species as supported by the data.

Impact of Climate Change on Apple Production in India: A Review

Significant variation in mean state of the climate or in its variability persisting for an extended period (typically decades or longer) is referred as climate change. It may be due to natural internal processes or external forcing or persistent anthropogenic changes in the composition of the atmosphere.1 Greenhouse gases like CO2, CH4, N2O, water vapours and ozone re-emit some of solar radiations in the form of short wave radiations to the earth surface and responsible for its warming.2 If they did not perform this useful function, most of the heat energy would escape, leaving the earth cold (about – 18oC) and unfit to support life.3 However, since the Industrial Revolution began about 150 years ago, man-made activities have added significant quantities of GHGs to the atmosphere. The atmospheric concentrations of CO2, CH4, N2O have grown by about 31%, 151% and 17%, respectively, between 1750 and 2000.1 Twenty years ago snowfall was regular phenomenon in high hills of Himachal Pradesh but in the last 20 years, only 2-3 instances of snowfall have been recorded.4 It has been recorded that the average maximum temperature rose by 0.58oC from the year of 1963 to 2007, whereas, the average minimum temperature rose by 2.75oC.5 Though, Kullu in northern Himachal Pradesh is well known for apple cultivation, but due to inadequate snowfall and improper chilling hours survivaling affected the cultivation of apple in the region.6 Chilling affects the flowering and subsequent fruit setting qualitatively as well as quantitatively.7have indicated that irregular bearing behavior of Starking Delicious is largely influenced by climatic conditions. The rain and hails during flowering adversely affects the fruit set, whereas, moderate temperature of 20oC with relatively low rains during flowering results in the good fruit set.8 The plants mortality rate due to drought was higher. The plants mortality rate due to drought was higher. About 80% of reduction in yield was estimated due to irrigation water shortage and 20% due to high evaporation rate in apples.4 reported decrease in chill unit hours in the apple growing areas of Himachal Pradesh. Most of the apple varieties require 1000-1600 hours (at or below 7.20C) of chill units depending upon the variety.9

Agro-metrological investigation of bumper apple productivity in Himachal Pradesh, India

The study aimed to investigate the productivity and weather relationship for the apple growing areas of Himachal Pradesh viz., Kalpa, Bhuntar and Shimla in district Kinnaur, Kullu and Shimla, respectively. The results revealed that pre bloom period (November to February) in the year 2009-10 remained cooler. The minimum temperature of 0.4 to 0.9, 1.0 to 1.1°C and 1.9 to 2.2°C and maximum temperature of 6.7, 1.0 to 1.1 and 1.7°C were lower in Shimla, Bhuntar and Kalpa region, respectively compared to 1995-2009.. The maximum temperature for the chill accumulation months of November, December, January and February during 2009-10 showed 13 to 19 per cent lower compared to 1995-2009. The average pre bloom rainfall during 2010 was 39 to 57 per cent higher than 1995-2009 indicating sustainable bloom period. The 3 to 4°C temperature rise during March 2010 (19 to 24°C) as compared to 1995-2009 (16 to 21.4°C) coupled with 52 per cent higher precipitation benefited the crop in profuse flowering and hence good fruit set. The average maximum temperature during the post bloom period (May-June) in 2009-10 was 1°C higher compared to the previous years coupled with 23 per cent higher rainfall resulting in an highest productivity. The highest productivity (8.57 MT/ha) during 2010 which was 58 per cent higher than the previous years can be ascribed due to the favorable low temperature in pre bloom period and increase in the temperature inthe month of March along with adequate rainfall in the bloom and post bloom period.

Managed bumblebees outperform honeybees in increasing peach fruit set in China: different limiting processes with different pollinators.

Peach Prunus persica (L.) Batsch is self-compatible and largely self-fertile, but under greenhouse conditions pollinators must be introduced to achieve good fruit set and quality. Because little work has been done to assess the effectiveness of different pollinators on peach trees under greenhouse conditions, we studied ‘Okubo’ peach in greenhouse tunnels near Beijing between 2012 and 2014. We measured pollen deposition, pollen-tube growth rates, ovary development, and initial fruit set after the flowers were visited by either of two managed pollinators: bumblebees, Bombus patagiatus Nylander, and honeybees, Apis mellifera L. The results show that B. patagiatus is more effective than A. mellifera as a pollinator of peach in greenhouses because of differences in two processes. First, B. patagiatus deposits more pollen grains on peach stigmas than A. mellifera, both during a single visit and during a whole day of open pollination. Second, there are differences in the fertilization performance of the pollen deposited. Half of the flowers visited by B. patagiatus are fertilized 9–11 days after bee visits, while for flowers visited by A. mellifera, half are fertilized 13–15 days after bee visits. Consequently, fruit development is also accelerated by bumblebees, showing that the different pollinators have not only different pollination efficiency, but also influence the subsequent time course of fertilization and fruit set. Flowers visited by B. patagiatus show faster ovary growth and ultimately these flowers produce more fruit. Our work shows that pollinators may influence fruit production beyond the amount of pollen delivered. We show that managed indigenous bumblebees significantly outperform introduced honeybees in increasing peach initial fruit set under greenhouse conditions.

Genetic Variability in some Indian Mango Cultivars and Hybrids

Mango is a perennial and highly heterozygous plant. Therefore, it takes a long time to breed a variety in this crop. Information on genetic variability among cultivars and hybrids helps plan meaningful crop improvement programmes. Due to the high heterozygosity, complexity of its flowers and poor fruit-set, the progeny population that can be raised from a cross is very meagre. Hence, there is a need to choose parents that have good fruit-set and show genetic divergence. It would also be interesting to establish if the hybrids generated are truly open-pollinated progenies, or arise from controlled crossing. Basic information thus obtained would help chalk out a potentially successful breeding programme. A study in this direction was carried out by using morphological characters of twelve hybrids and their respective parents. Cluster analysis indicated a relationship between the parents and hybrids. Two major clusters were observed from the clustering pattern. In the first cluster, varieties Dashehari, Banganapalli, Manjeera, Sindhu, Janardhan Pasand, Ratna, Rumani, Amrapali, Neelgoa and Alphonso grouped together. The second cluster consisted of vars. Arka Aruna, Neelum, Arka Puneet, Neeleshan, Mulgoa, Mallika, Arka Anmol and Arka Neelkiran. The hybrid, Sindhu was observed to be genetically closer to Ratna than to Alphonso. The sub-clustering pattern also showed a close relationship between parents and their hybrids. The hybrid, Arka Anmol, was found to distantly placed from the centre (8.54), as also the hybrid, Arka Neelkiran (7.05). 'Sindhu' was also found to be closer to the centre (1.55).

Yucca aloifolia (Asparagaceae) opts out of an obligate pollination mutualism.

• According to Cope's 'law of the unspecialized' highly dependent species interactions are 'evolutionary dead ends,' prone to extinction because reversion to more generalist interactions is thought to be unlikely. Cases of extreme specialization, such as those seen between obligate mutualists, are cast as evolutionarily inescapable, inevitably leading to extinction rather than diversification of participating species. The pollination mutualism between Yucca plants and yucca moths (Tegeticula and Parategeticula) would seem to be locked into such an obligate mutualism. Yucca aloifolia populations, however, can produce large numbers of fruit lacking moth oviposition scars. Here, we investigate the pollination ecology of Y. aloifolia, in search of the non-moth pollination of a Yucca species.• We perform pollinator exclusion studies on Yucca aloifolia and a sympatric yucca species, Y. filamentosa. We then perform postvisit exclusion treatments, an analysis of dissected fruits, and a fluorescent dye transfer experiment.• As expected, Yucca filamentosa plants set fruit only when inflorescences were exposed to crepuscular and nocturnal pollinating yucca moths. In contrast, good fruit set was observed when pollinators were excluded from Y. aloifolia inflorescences from dusk to dawn, and no fruit set was observed when pollinators were excluded during the day. Follow up experiments indicated that European honeybees (Apis mellifera) were passively yet effectively pollinating Y. aloifolia flowers.• These results indicate that even highly specialized mutualisms may not be entirely obligate interactions or evolutionary dead ends.

Examination of the Suitability of Different Pollinators for Four Sweet Cherry Cultivars Commonly Grown in Poland

Abstract The aim of the work was to select pollinators for sweet cherry cultivars: ‘Vanda’, ‘Techlovan’, ‘Syl–via’ and ‘Regina’, which are of great economic significance in Poland. As pollinators, three or four different cultivars with the same or similar flowering time as the pollinated cultivars were evaluated annually. The pollinators belonged to different incompatibility groups. Pollination was carried out over four consecutive seasons. Assuming that for a good yield more than 20% of the flowers should develop fruits, a good polli–nator for the cv. ‘Vanda’ was ‘Techlovan’, and for the cv. ‘Regina’ - ‘Sylvia’. The cv. ‘Techlovan’ was pollinated to best effect by ‘Vega’, and the cv. ‘Sylvia’ by ‘Regina’, but the setting of fruits in the last two combinations was moderately good. Low to moderately good fruit setting but depending on the year was observed in the combinations ‘Sylvia’ x ‘Summit’, ‘Regina’ x ‘Summit’, and ‘Regina’ x ‘Rainier’. Cultivar ‘Summit’ for ‘Sylvia’, and ‘Summit’ and ‘Rainier’ for the cv. ‘Regina’ should not be used as pollinators because the low percentage of fruit set obtained annually does not guarantee a satisfactory yield.

Development of interspecific F1 hybrids (Solanum melongena × Solanum khasianum) in eggplant through embryo rescue technique

The wild relatives of eggplant possess number of unexploited resistant genes against biotic and abiotic stresses. These wild relatives are either not easily crossable and produces sterile F1 when crossed with cultivated genotypes. The present study was executed with the objective of standardization of protocol and obtaining hybrids of Solanum melongena and Solanum khasianum through embryo rescue technique. The cross pollination between indegenous colloections of S. melongena and locally collected S. khasianum was carried out in a reciprocal manner. Out of 25 indegenous genotypes, IC 203585, IC 261767, IC 261797, IC 305129, IC 354611, IC 099736 and IC 261888 showed good fruit setting when S. khasianum was used as male. However, no fruit setting was observed when S. khasianum used as female parent and most of the fruits dropped within 35 days after pollination. The hybrid combinations, viz. IC 203585 × S. khasianum, IC 261767 × S. khasianum, IC 261797 × S. khasianum and IC 305129 × S. khasianum gave the best results when inoculated after 25 days after inoculation. Maximum shoot regeneration was observed to the tune of 80.01 ± 0.108 in IC 261797 × S. khasianum when inoculated on MS media supplemented with 2 mg/l BAP + 0.5 mg/l IAA. However, the highest root regeneration was observed in IC 203585 × S. khasianum to the extent of 78.45 when inoculated on media MS + 2.5 mg/l kinetin + 1 mg/l IAA.

CURRENT STATUS OF DURIAN BREEDING PROGRAM IN THAILAND

Selection and evaluation of 1st and 2nd generation F1 hybrids and study on inheritance characteristics were selected and released with the desirable characters: early, moderate and late maturity, good eating quality, fine flesh texture, good fruit setting and phytophthora tolerant characters for durian production in Thailand during 2006 to 2010. Promising early maturity lines are hybrid No. 12-21-1 and 10-432-6, moderate maturity lines are hybrid No. 11-341-1 and 11-241-9 and late maturity lines is 5-441-13. Promising F1 hybrids of durian for processing is hybrid no. 5-451-5. Promising F1 hybrids with most tolerance to Phytophthora palmivora is IIICN5-4-3-6. Selection and evaluation of F2 durians showed that the hybrids No. 5-441-13-16-2 and 5-441-13-14-4 had growth, flowering and yield better than others. Regional yield trial for promising F1 hybrids of durian for production and export showed that hybrid no 6-413-7 grew better than others. Fertilizer response of selected F1 hybrids of durian showed that ‘Monthong’ was the most to respond to the fertilizer followed by ‘Chanthaburi 1, 2 and 3’ and nutrient content of soils showed that nitrogen most affected growth of durian. Effect of Phytophthora disease on selected F1 hybrids of durian showed that hybrid No. IIICN5-4-3-6 was the most tolerant on the stem and leaves. Commercial comparison for yield and marketable acceptance of new F1 hybrids of durian showed that ‘Chanthaburi 1’ grew better than others. Substitute of original cultivar with new F1 hybrids of durian showed that side grafting technique was successfully between 20-70%. Up to the present, based on evaluation from durian data during 2006 to 2010, it is expected that at least three promising lines of F1 hybrid cultivars will be released as new recommended durian cultivars in 2012 and will be officially named as ‘Chanthaburi 4’, ‘Chanthaburi 5’ and ‘Chanthaburi 6’.

Caracterização anatômico-fisiológica da compatibilidade reprodutiva de ameixeira-japonesa

O objetivo do trabalho foi caracterizar fisiologicamente a compatibilidade reprodutiva de sete cultivares de ameixeira-japonesa (Prunus salicina Lindl) por meio de hibridações, análise de frutificação efetiva e do crescimento de tubos polínicos (CTP). O frui set foi determinado 40 dias após as hibridações controladas, realizadas a campo. O grau de compatibilidade foi avaliado invivo, para determinar o CTP. A cv. América apresentou bom fruit set quando polinizada com as cvs. Rosa Mineira (26,7%), Amarelinha (8,7%) e Reubennel (12,7%). Os cruzamentos 'Gulf Blaze' x 'Gulf Rubi', 'Gulf Rubi' x 'Gulf Rubi' e 'Gulf Rubi' x 'Gulf Blaze' obtiveram um fruit set de 11,36%, 3,84% e 9,94%, respectivamente. Na polinização em laboratório, os tubos polínicos atingiram o óvulo ou ovário nesses cruzamentos, com exceção da autopolinização da 'Gulf Rubi'. No campo, não houve frutificação efetiva na autopolinização da 'América' e 'Gulf Blaze' e no cruzamento da 'América' x 'Pluma 7'. Os tubos polínicos nesses cruzamentos não chegaram a atingir o óvulo, com exceção da autopolinização da 'Gulf Blaze'. Concluiu-se que apenas os cruzamentos entre 'América' x 'Pluma 7' são incompatíveis, e a cultivar América é autoincompatível.