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Studies on fruit set in coconut upon artificial pollination in various cross combinations

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Abstract

Studies on fruit set in coconut have important implications in nut yield. A detailed study was carried out to determine the fruit set in coconut as influenced by variety, cross combination, climatic variables such as rainfall, temperature and relative humidity. Artificial pollination was carried out on selected parental palms of West Coast Tall (WCT), Chowghat Green Dwarf (CGD) and Chowghat Orange Dwarf (COD) in farmer's plots over a period of five years commencing from 1996-2000. The various cross combinations tried among the three varieties, viz., WCT, CGD and COD were three selfing, two inter se and three crosses. The mean fruit set for the different cross combinations was 24.67%. The maximum fruit set (39.54%) was in COD (self) followed by WCT (self) and COD × WCT, and minimum in CGD × WCT (19.16%) indicating that COD variety as a female parent gave significantly higher fruit set compared to other varieties. Generally, the varieties WCT and CGD under selfing gave a higher fruit set (27.43 and 24.65%) when compared to inter se (21.63 and 21.22%). Fruit set was maximum (28.73%) during March and minimum (18.80%) during May but the year-to-year variation was not significant. The bimonthly average relative humidity (%), number of rainy days and rainfall (cm) had a significant negative correlation (-0.504, -0.428, -0.395, respectively) with fruit set. Studies also revealed that there was a significant reduction in fruit set to the tune of 35%, when climatic conditions are not favourable. The present investigations revealed that fruit set in coconut vary significantly due to genotype, cross combination and climatic variables.
... At present, artificial pollination for the production of coconut hybrids involves bagging and this is one of the major reasons for the decrease in fruit setting. The increase in temperature and humidity (microclimate) inside the pollination bag is detrimental to the fruit setting (Thomas et al. 2012). This laborious process of bagging and pollen application can be dispensed with if honey bees colonies can be placed in coconut seed gardens for enhancing the pollination and fruit setting. ...
Chapter
Pollination is one of the ecosystem services that benefits the wellness of mankind by evolving adaptive diversity and heterogeneity in crops and boosts productivity as well. Understanding floral and reproductive biology in coconut and the role of foraging insects on blooming flowers are key functionaries for effective fertilization, nut set and diversity induction. Being a cross-pollinated crop (96%), a wide array of insects forage harnessing the abundant pollen and limited nectar present on coconut flowers thereby aiding pollination. The most abundant insects were those belonging to Hymenoptera (89.8% honey bees, Apis spp. Including stingless bees, Tetragonula sp.) and the rest consisted of Branconidae (wasps, Vespoidea including Pollistes spp.), Formicideae (ants), and those belonging to Hemiptera and Thysanoptera (1.0% each), Diptera (4.9%), and Coleoptera (4.3%). Ants did not have any effect on nut production. Insect populations were maximum during the rainy (July–October) season. Ants predominate dwarfs and bees are dominant on tall genotypes. Association of a weevil, Amorphoidea coimbatorensis on male flowers of coconut inflorescence is common and its role in pollination cannot be ruled out. Role of varietal scent and floral volatiles attributed to enhanced insect visitations. Installation of beehives and crop pluralism including eco-feast crops provide a continuous food source and encourage effective pollination services in coconut. From the evolutionary perspective, the adoption of the opportunistic pollination system by the coconut, can be reckoned as a survival strategy of this monotypic species.
... Among the hybrids, LCT x COD recorded significantly the lower yield (54.3 nuts palm -1 year -1 ) and was on par with MYD x WCT (59.3 nuts palm -1 year -1 ) and ECT x MYD (62.1 nuts palm -1 year -1 ). The variation in fruit set percentage among coconut hybrids were earlier reported by Nair et al. (2003) and Thomas et al. (2012). In coconut, inter-spadix overlapping of female and male phase is an important factor affecting fruit set along with cross-pollination, where the pollen from nearby palms are transferred by agents like wind, insect etc. (Henderson, 1988;Nagwekar et al., 2002). ...
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Field studies conducted for a period of 12 years to assess the traits responsible for yield performance and heterosis of twelve coconut hybrids in comparison with three varieties showed that among the hybrids, GBGD x ECT recorded the highest mean yield of 127.6 nuts palm-1 year-1 and was on par with ECT x GBGD (106.9 nuts palm-1 year-1), COD x LCT (108.0 nuts palm-1 year-1) and WCT x MYD (107.6 nuts palm-1 year-1). Hybrid GBGD x PHOT recorded the highest fruit length (23.9 cm) followed by ECT x GBGD (23.3 cm). The hybrid ECT x GBGD recorded the highest values for most of the fruit characteristics viz., fruit breadth (17.3 cm), fruit weight (1180.0 g), husked fruit weight (758.0 g) and copra weight (231.1 g). The variety 'Laccadive Ordinary' recorded higher oil content (71.1%) compared to its hybrids, LCT x GBGD (70.8%), COD x LCT (70.0%) and LCT x COD (69.8%). Hybrids displayed substantial differences in their heterotic response for nut characters. The highest yielding hybrid, GBGD x ECT excelled its standard check by 40.8 per cent followed by LCT x COD (39.4%).
... influencing the nut yield, and in the present study, it was within the range from 31.5 to 38.7, and the maximum fruit set was obtained in ECT × GBGD and the lowest in WCT × MYD. However, variations in the fruit set percentage of different cross combinations in coconut were also observed (Thomas et al., 2012;Nath et al., 2017;Sumitha et al., 2020). In coconut, inter-spadix overlapping of female and male phases is important for fruit set and cross-pollination from nearby palms (Henderson, 1988). ...
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A coconut-based integrated farming system (IFS) model suited for lowlands was developed at the Integrated Farming System Research Station (IFSRS), Karamana, Kerala State, India, under Kerala Agricultural University. The area of the model was decided as 0.2 ha, matching the average per capita land availability of a marginal farmer in the State. Apart from the major crop coconut, intercrops, such as vegetables, fruit crops, spices, fodder and tuber crops were included in the model. The allied enterprises integrated were livestock, azolla, and agroforestry. Tree components of the model comprised of teak, jack, breadfruit, garcinia and mango. Research data for five years revealed that the model generated food products above the requirement of a four-member family, and the surplus production could contribute to farmer’s income. The productivity under the IFS model was enhanced ten-folds compared to that under the sole crop of coconut for the same area. Plant nutrients were generated within the farm through organic recycling, which contributed to the substantial saving of chemical fertilizers. The system was found climate-smart because of reduced use of chemical fertilizers and net negative emission of greenhouse gases mostly achieved through agroforestry. This IFS model could also ensure considerable employment generation. The model could be adopted by farmers of lowland tracts of Kerala having similar agro-climatic features for better economic returns and environmental benefits.
... influencing the nut yield, and in the present study, it was within the range from 31.5 to 38.7, and the maximum fruit set was obtained in ECT × GBGD and the lowest in WCT × MYD. However, variations in the fruit set percentage of different cross combinations in coconut were also observed (Thomas et al., 2012;Nath et al., 2017;Sumitha et al., 2020). In coconut, inter-spadix overlapping of female and male phases is important for fruit set and cross-pollination from nearby palms (Henderson, 1988). ...
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Cocos nucifera L. is a perennial oil yielding crop with a long productive life span (>60 years); thus, identifying a suitable high yielding hybrid to a particular agro-climatic region plays a prime role in achieving sustainable coconut yield. In this context, an evaluation trial with varietal cross combinations involving Tall × Dwarf (six crosses) and Dwarf × Tall (two crosses) was conducted at All India Coordinated Research Project (AICRP) on Palms, Bhubaneshwar Centre, Odisha, for 15 years. The experiment was laid out in randomized block design with four replications maintaining six palms per replication. Observations on yield and yield attributing characters during 2018 to 2020 revealed the superior performance of ECT × GBGD (99.1 nuts), which was followed by ECT × MYD (86.9 nuts) over the local check (ECT) by recording higher nut yield. Copra output per palm was significantly the highest under ECT × GBGD (20.6 kg palm-1), followed by LCT × COD (18.6 kg palm-1). Hybrids possessed a higher quantity of organoleptically 'good' tender nut water (270.3 to 354.1 mL) with TSS of 5.8 to 6.9 °Brix, 25.4 to 34.0 ppm of sodium and 2065.9 to 2885.0 ppm of potassium.
... In high rainfall zones, particularly in the western coast of India, coconut hybridization work is carried out only for six months from November to May and pollination work is suspended during rains from June to October. In Southern Kerala,where there is intermittent rainfall even during the dry months (November and May), the fruit set was only 18-19 per cent (Thomas et al., 2012) compared to an average fruit setting of 25 per cent obtained upon artificial pollination in other areas (Nair et al., 2003). The use of polythene covers to prevent wetting of pollination bag has met with little success due to lifting and tossing of the polythene covers during heavy winds and high humidity which accumulates thereupon, that prevents efficient fruit setting. ...
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Any ecosystem offers several goods and services to human beings. Ecosystem services are broadly categorized as Provisioning Services, Regulatory services, Cultural services, and Supporting services. Provisioning services include the food, vegetables, fruits, wood, and livestock which are the direct products of ecosystems. Regulatory services include regulation of climate, water, pests/disease and pollination including carbon sequestration. Cultural Services include various services which are of either educational, aesthetic, cultural heritage including tourism, and recreation. Supporting services include biodiversity, nutrient cycling, and soil formation. Agroforestry systems especially coconut and arecanut gardens offer ample scope for diversifcation in terms of cropping systems, farming systems, products. Agro-ecosystems also offer multitude of services to us of which few are studied measured and analyzed. Many of the services are taken for granted and not valued. The current compilation explore the ecosystem services as applicable perennial agro-ecosystems especially agroforestry systems and diversifed coconut and arecanut gardens. The book is designed to expose the readers to Ecosystem concepts including quantifcation techniques, and introduce the concepts such as various cropping system diversifcation options in coconut, arecanut gardens, scope of homestead farming systems, agroforestry systems, fsh farming in coconut gardens, aquaculture, carbon sequestration potential in agroforestry systems, pollination services, nutrient management in spices, litter dyramics in plantation and agroforestry systems, coconut leaf vermicompost, economic analysis in cropping systems, and machine learning tools for data analysis.
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Full-text available
Cocos nucifera, one of the most important plantation crops is cross pollinated and has a diploid chromosome complement of 2n = 2x = 32. Doubled-haploid coconut plants are produced at low frequency through anther culture. Non-embryogenic fast-growing calli (FGC) are also produced in anther culture. The present study was undertaken to induce embryogenic calli from these FGC and to test their origin. The FGC were subjected to heat pretreatment at 38 °C for 3 and 6 days and cultured on three media with different plant growth regulator combinations in liquid, solid and liquid layered on solid (layered) culture, and with different sucrose concentrations. Highest callogenesis and weight increase in FGC was achieved after heat pretreatment of intact FGC cultured in solid Eeuwen's Y 3 medium supplemented with 100 µM 2,4-dichlorophenoxyacetic acid. Weight increase of FGC was negatively correlated with sucrose concentration. Incorporation of cytokinins facilitated the conversion of FGC to embryogenic callus. Histological studies revealed that these embryogenic calli consisted of a cambium-like zone, a characteristic feature of embryogenic calli. Flow cytometry confirmed that embryogenic calli derived from FGC originated from reduced microspores. Therefore, FGC are a good source of explant for the production of doubled-haploid plants of coconut over an extended period.
Article
Full-text available
Cocos nucifera, one of the most important plantation crops is cross pollinated and has a diploid chromosome complement of 2n = 2x = 32. Doubled-haploid coconut plants are produced at low frequency through anther culture. Non-embryogenic fast-growing calli (FGC) are also produced in anther culture. The present study was undertaken to induce embryogenic calli from these FGC and to test their origin. The FGC were subjected to heat pretreatment at 38 °C for 3 and 6 days and cultured on three media with different plant growth regulator combinations in liquid, solid and liquid layered on solid (layered) culture, and with different sucrose concentrations. Highest callogenesis and weight increase in FGC was achieved after heat pretreatment of intact FGC cultured in solid Eeuwen's Y 3 medium supplemented with 100 µM 2,4-dichlorophenoxyacetic acid. Weight increase of FGC was negatively correlated with sucrose concentration. Incorporation of cytokinins facilitated the conversion of FGC to embryogenic callus. Histological studies revealed that these embryogenic calli consisted of a cambium-like zone, a characteristic feature of embryogenic calli. Flow cytometry confirmed that embryogenic calli derived from FGC originated from reduced microspores. Therefore, FGC are a good source of explant for the production of doubled-haploid plants of coconut over an extended period.
Article
Full-text available
Cocos nucifera, one of the most important plantation crops is cross pollinated and has a diploid chromosome complement of 2n = 2x = 32. Doubled haploid coconut plants are produced at low frequency through anther culture. Non-embryogenic fast-growing calli (FGC) are also produced in anther culture. The present study was undertaken to induce embryogenic calli from these FGC and to test their origin. The FGC were subjected to heat pretreatment at 38 °C for 3 and 6 days and cultured on three media with different plant growth regulator combinations in liquid, solid and liquid layered on solid (layered) culture, and with different sucrose concentrations. Highest callogenesis and weight increase in FGC was achieved after heat pretreatment of intact FGC cultured in solid Eeuwen's Y3 medium supplemented with 100 µM 2,4-dichlorophenoxyacetic acid. Weight increase of FGC was negatively correlated with sucrose concentration. Incorporation of cytokinins facilitated the conversion of FGC to embryogenic callus. Histological studies revealed that these embryogenic calli consisted of a cambium-like zone, a characteristic feature of embryogenic calli. Flow cytometry confirmed that embryogenic calli derived from FGC originated from reduced microspores. Therefore, FGC are a good source of explant for the production of doubled haploid plants of coconut over an extended period.
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