Browsing by Author "Aswini, A"

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Abiotic stress tolerance in mango (Mangifera indica L.) rootstocks
(Department of Fruit Science, College of Agriculture ,Vellanikkara, 2024-03-02) Chetan Hanamant, B Patil.; Aswini, A
Mango (Mangifera indica L.) a tropical fruit crop with immense economic and cultural value, is extensively grown in a wide range of agro-climatic zones. Mango seedlings are resilient to a variety of environmental conditions, but they frequently face difficult obstacles due to abiotic stress factors. It is extremely concerning that this crop's productivity has been dropping over the last few years. Considering these problems into account, a study entitled “Abiotic Stress tolerance in mango (Mangifera indica L.) rootstocks” was carried out in the Department of Fruit Science during 2022-23, constituting three experiments namely, Screening of mango genotypes for tolerance to salinity, flooding and drought. All the set of three experiments were conducted using factorial completely randomized design (FCRD) with two factors: genotypes viz., V1- Moovandan, V2- Olour, V3- Kurukkan, V4- Chandrakaran, V5- Vellaikolumban, V6- Bappakai, V7- H-66, and abiotic stress. In the first experiment, mango genotypes were evaluated for different levels of salinity stress viz., S0- Control, S1- 2 dSm-1, S2- 4 dSm-1, S2- 4 dSm-1, and S4- 8 dSm-1 NaCl. Salinity was induced in the soil by quantifying the EC and pH of the soil. Growth characters had shown significant difference among genotypes. The highest seeding height (26.05 cm) was recorded in Moovandan, seeding girth (0.39 cm) was recorded in Bappakai, number of leaves (22.58), vigour index (2811.37), was observed in H-66, seedling girth (0.44 cm), number of sprouts (2.87) and internodal length (5.26 cm) in Chandrakaran. Physiological parameters further revealed that, leaf area (52.06 cm2) in Vellaikolumban. leaf area index (2.85) in H-66, Stomatal conductivity (0.127 molm-2s-1) and leaf transpiration rate (2.08 µmolm-2s-1) in Moovandan, net photosynthetic rate (6.74 µmolm-2s-1) in Olour recorded to maximum. On estimation of biochemical characters viz., phenol content and proline content was increased on increasing level of salinity. Higher phenol content (16.53 mg/g) and proline content (1.53 µmol/g) in was noticed in Bappakai. While, chlorophyll content (4.46 mg/g) was highest in Chandrakaran. Among the higher salinity stress Moovandan performed the
Dragon fruit is an exotic fruit crop commonly referred to as Pitaya, is perennial in naturewith a life span of 20 years
(Department of Fruit Science, College of Agriculture , Vellanikkara, 2023-03-02) Aarthi, M.; Aswini, A
Dragon fruit is an exotic fruit crop commonly referred to as Pitaya, is perennial in naturewith a life span of 20 years. The production of dragon fruit is on the increase in Kerala due to its wide adaptability and high nutritional properties. As it is an exotic fruitcrop, the information on flowering, phenology and ideal genotypes under Kerala condition is lacking. So information on genotypes and reproductive biology of dragon fruit will be aboon to farmers and also to the researchers for future breeding programmes. The current investigation entitled “Reproductive biology and evaluation of dragon fruit (Hylocereus spp.) genotypes” conducted in the college orchard of the Department of Fruit Science, Vellanikkara during the period of 2021- 2023 throws light on this aspect. Two experiments were conducted as a part of the study, one for assessing the yield and quality of different dragon fruit genotypes,and the other for investigating the reproductive biology and phenology of different dragon fruitgenotypes. Five dragon fruit genotypes, namely Cambodian Red, Malaysian Red, Oregano Red, Srilankan Red and Cambodian White were evaluated during this research study. In the first experiment, when the different parameters related to stem, yield and quality were studied, significant variations could be observed among the genotypes. With regard to quantitative stem characteristics, Cambodian White exhibited highest stem segment width (33.05 mm), arch height (4.62 cm) and distance between areoles (35.08 mm) and the least number of spines per areole (2.13). When qualitative stem characteristics were considered, Oregano Red exhibited strong waxiness with a flat margin and prominent dark brown colouredspines on areoles making it distinctly different from the other genotypes. When the quantitative fruit characteristics were observed Oregano Red produced fruits having highest fruit width (8.62 cm), fruit girth (27.84 cm) and number of bracts on fruit (28.07cm), whereas minimum fruit width (6.65 cm) and fruit girth (22.34 cm) were recorded in Malaysian Red. The highest bract width was recorded in Cambodian White (35.00) with less number of bracts in fruits (19.21), and lowest bract width was observed in Malaysian Red (25.52). The length of apical bract was highest in Cambodian Red (42.66 mm), whereas it wasabsent in Oregano Red. Among the fruit parameters studied, highest fruit weight (411.33 g), peel weight (134.82g) and pulp weight (276.47g) were recorded in Oregano Red and lowest in Malaysian Red. Cambodian Red recorded the highest number of seeds (2045 per 50 g of fruit pulp) but small in size, whereas Oregano Red had the least number of seeds (820.00 per 50 g of fruit pulp) but larger in size. The pulp to fruit weight ratio was highest in Cambodian Red (0.74) followed by Srilankan Red (0.72), indicatingthe presence of thin peel in these genotypes. On contrary, Cambodian White had the lowest pulp to fruit weight ratio (0.63) indicating the presence of thick peel in this genotype. Regarding the number of fruits per pole, Malaysian Red recorded the maximum numberof fruits per pole (17.60), followed by Cambodian Red (11.8). However, the fruit yield (kg per pole), of both Cambodian Red (3.79 kg) and Malaysian Red (3.68 kg) were found to be on par.This result revealed that Malaysian Red produced smaller fruits when compared to Cambodian Red. The number of fruits per pole were least in Oregano Red (3.6 fruits per pole) and was onpar with Srilankan Red (4.6 fruits per pole) resulting in reduced yield in Oregano Red (1.29 kg/pole) followed by Srilankan Red (1.54 kg per pole). Oregano Red and Cambodian White were distinct from the other genotypes with respectto fruit morphological features. With regards to the position of the fruit bract towards the peel,the bracts were slightly held out in Cambodian White, while bracts were strongly held out in Oregano Red. Considering the peel and pulp colour, Cambodian White had medium pink colour with white flesh, whereas, Oregano Red exhibited red coloured peel and dark pink pulp.Regarding the shape of the fruit, Cambodian White produced oblong fruits, while the fruits of Oregano Red were spherical in shape. Biochemical analysis of the fruits clearly indicated that there exists significant variationsamong the dragon fruit genotypes with respect to total soluble solids (TSS), TSS/acid ratio and anthocyanin content. Srilankan Red and Cambodian White recorded the highest and lowest values respectively for both TSS (13.78 °Brix and 10.18 °Brix) and TSS/acid ratio (107.66 and79.55). Oregano Red recorded the highest anthocyanin concentration (0.27 mg/g), whereas Cambodian White (0.01 mg/g) recorded only very low concentration of anthocyanin. Other biochemical parameters, such as acidity, ascorbic acid content, reducing sugar and total sugardid not exhibit any significant variation among the genotypes. In the second experiment, flower characteristics such as flower bud length and girth, pericarpel width, length of perianth, distance of anther below stigma, number of stigma lobes,number of flower flushes and the number of flowers per pole varied among the genotypes. Withregards to flower production, Malaysian Red produced highest number of flowers (23.0 flowersper pole) while Srilankan Red produced less number of flowers (4.8 flowers per pole). The number of flower flushes per year varied among the genotypes, where Cambodian Red and Malaysian Red recorded seven flower cycles per year, Srilankan Red and Cambodian White exhibited five flower cycles per year, while in Oregano Red only four flower flushes were observed per year. In terms of qualitative flower characteristics, Cambodian White and Oregano Red were found to significant vary from the other genotypes. Both Oregano Red and Cambodian White exhibited circular bud shape with rounded apex. Regarding the flower colour, the primary colour of sepals and petals of both genotypes were green and white, respectively, whereas the secondary colour of sepal in Oregano Red exhibited a strong red edge on sepals, and that of Cambodian White featured no red colour on the sepals. The sex form, nature of stamen and shape of the bract did not differ among all the genotypes. Hermaphrodite sex form with free stamen was observed in all the dragon fruit genotypes under study. Phenological parameters clearly indicated that there exists variation among the genotypes. Early bud initiation was recorded in Malaysian Red (291.6 days) and late bud initiationobserved in Oregano Red (388.0 days). From the observation recorded, the genotype OreganoRed was observed to take maximum number of days for flowering (18.00), fruit set (4.06) and harvest (28.22 days) when compared to other genotypes. Cambodian White (26.34 days) took only minimum number of days for fruit harvest from fruit set. During the study period flowering season was observed to start from the month of May for Malaysian Red and Cambodian Red and in Oregano Red flowering was delayed and found to start only in the last week of June. The fruiting season of Cambodian Red and Malaysian Red started from June and continued up to last weekof October while in other genotypes flowering started from July and continued till October. In the pollen study, the highest pollen viability of 100% was observed in Oregano Red, Srilankan Red and Cambodian White. The genotypes did not significantly vary for pollen sizeand length of pollen tube, as it ranged from 0.08 to 0.09 mm and 0.203 to 0.250 mm respectively. In the compatibility study, all self and cross pollinations resulted in successful fruit set (100%), except for Oregano Red which exhibited only 33.3% self compatibility. Cluster analysis of stem, flower and fruit qualitative characters provided four clusters at 70 % similarity coefficient and it could be inferred that, Cambodian Red and Malaysian Red were closely related to each other, indicating a possibility of belonging to the same species. The other clusters were found to exhibit variations among them, even though, they originated from the same species, indicating the presence of more than one genotype in the same species. Based on the current research, it can be inferred that the best genotype with the highest yield and largest fruits was Cambodian Red. Oregano Red was found to have the highest anthocyanin concentration and Srilankan Red recorded the highest total soluble solids, makingboth suitable for value addition. Despite being members of the same species (H. costaricensis),the morphological characteristics of Malaysian Red, Srilankan Red and Cambodian Red differed from one another. Oregano Red (H. polyrhizus) and Cambodian White (H. undatus) displayed wide genetic variation as they belong to different species. Morphological, biochemical and phenological characterization of five dragon fruit (Hylocereus spp.) genotypes revealed the presence genetic variations among them which could be used as a key trait for distinguishing three different species.
Ecophysiology and screening for climate change resilience in Mango (Mangifera indica L.) genotypes
(Department of Pomology and Floriculture College of Agriculture,Vellayani, 2019) Aswini, A; Jyothi Bhaskar
Morpho-molecular characterization of jackfruit (Artocarpus heterophyllus Lam.) accessions
(Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 2015) Aswini, A; Lila Mathew, K
Morphological and biochemical characterization of exotic fruit crops of sapotaceae family
(Department of Fruit Science, College of Agriculture ,Vellanikkara, 2025-02-10) Amal Kishore, M.; Aswini, A
The Sapotaceae family includes a variety of tropical fruit crops known for their ecological and nutritional importance. Among these, abiu (Pouteria caimito) and star apple (Chrysophyllum cainito) are gaining attention for their unique qualities and potential benefits. These fruits are rich in nutrients, including phytochemicals, vitamins, minerals, and antioxidants, which make them valuable for promoting health and diversifying agricultural systems. Kerala's tropical climate provides favorable conditions for cultivating abiu and star apple, making them suitable additions to the state’s fruit crops. These fruits contribute to biodiversity while offering new market opportunities for farmers. Their distinct flavors and high nutritional value make them attractive to consumers, often commanding premium prices and increasing farm incomes. Although these fruits are now being grown commercially in Kerala, there is limited research on their growth, flowering, fruiting, and yield under local conditions. Understanding these aspects is essential to improve their cultivation and realize their full potential. The study on abiu (Pouteria caimito) was carried out across four distinct agroecological locations in Kerala: Kottayam, Thrissur, Malappuram, and Kozhikode. A total of 34 genotypes were collected from these regions and was evaluated for their morphological, biochemical, physiological, and phenological traits. Analysis of the genotypes revealed significant variability across morphological, biochemical, and other characteristics, highlighting the diversity present within these collections. The yield of abiu trees varied significantly across genotypes, highlighting their diverse genetic potential for production. Collection 01 stood out with the highest yield of 301.24 kg/tree, followed by Collection 26 (57.70 kg/tree) and Collection 11 (40.08 kg/tree), which also demonstrated strong productivity. Additionally, Collections 1, 15, 26, and 25 were identified as having exceptional yield characteristics, while Collections 21 and 19 recorded the lowest yields of 1.36 kg/tree and 3.62 kg/tree, respectively. These findings emphasize the importance of prioritizing high-yielding genotypes such as Collection 01 to enhance commercial productivity. Similarly, there was considerable variation in biochemical characteristics such as total soluble solids (TSS), acidity, antioxidant content, total phenolic content, total sugar, flavonoids, and fruit protein among the abiu collections. TSS, an essential biochemical trait, ranged from 7.06 OBrix to 13.08 OBrix, with Collection 11 exhibiting the highest value. Acidity varied from 0.097 per cent to 0.102 per cent, with Collection 02 showing the maximum level. Antioxidant content was highest in Collection 06 at 7.02 AA mg/100g, which also recorded the maximum total phenolic content of 1.03 mg/g. Total sugar content ranged from 4.46 per cent to 11.16 per cent, with Collection 07 leading in this trait, while flavonoid content peaked at 0.97 mg/g in Collection 17. Fruit protein content showed significant variation, with Collection 14 having the highest value of 1.90 mg/g. Based on these biochemical traits, Collections 11, 02, 06, 07, 17, and 14 were identified as superior genotypes. There was significant variation in physiological parameters such as relative water content, excised leaf water loss, membrane stability index, leaf thickness, lipid peroxidation, and epicuticular wax content among the abiu collections. Relative water content ranged from 54 per cent to 92 per cent , with Collection 30 recording the highest value. Excised leaf water loss was minimal in Collection 01 at 0.55 per cent, while membrane stability index was the highest in Collection 07 at 84.39 per cent. Leaf thickness varied from 205 × 10⁻³ mm to 280 × 10⁻³ mm, with Collection 33 showing the greatest thickness. Lipid peroxidation values ranged from 0.0093 mg/g to 0.0143 mg/g, with Collection 05 having the lowest value, indicating better oxidative stress tolerance. Epicuticular wax content showed notable variability, with Collection 30 having the maximum value of 0.57833 mg/g. Based on these physiological traits, Collections 30, 01, 07, 33, and 05 were identified as superior genotypes. The dendrogram analysis grouped the genotypes into four clusters. Cluster I contained five genotypes (11, 7, 22, 30, 33), while Cluster II had sixteen genotypes (27, 28, 18, 23, 34, 5, 26, 29, 31, 19, 20, 8, 16, 17, 24, 25). Cluster III comprised only one genotype, Collection 01, highlighting its unique traits, and Cluster IV included the remaining genotypes (14, 4, 10, 9, 12, 21, 32, 6, 13, 15). This analysis underscores the genetic diversity among the collections, with Cluster III being particularly distinct. ELISA was conducted on fruiting and non-fruiting types of Pouteria caimito to study hormonal variations. The analysis showed clear differences in hormone levels between the two types. Auxin was higher in the petiole and flower head of fruiting types, highlighting its role in supporting cell growth and development necessary for fruiting. However, auxin levels in the whole flower and ovary were similar in both types, suggesting that other factors may influence fruit formation in these parts. Cytokinin levels also showed variation, with fruiting types having more cytokinin in the ovary, aiding cell division and fruit development. In contrast, non-fruiting types had higher cytokinin levels in the petiole and flower head, possibly diverting resources and reducing fruiting success. This study demonstrates how auxin and cytokinin distribution in different plant parts influences the fruiting process in abiu. Anatomical studies of abiu fruit stalks showed significant differences between fruit-setting and non-fruit-setting types. Non-fruit-setting types had a smaller section diameter (1747.89 µm vs. 3437.60 µm), lower vesicle density (0.000244 vesicles/µm² vs. 0.000893 vesicles/µm²), and smaller vesicle diameter (29.4 µm vs. 38.09 µm). These structural differences highlight their role in fruit development. The study on star apple (Chrysophyllum cainito) was conducted with nine collections, eight of which were sourced from different parts of Thrissur, and one from Kozhikode in Kerala. These genotypes were systematically evaluated for their morphological, biochemical, physiological, and phenological traits. The analysis revealed significant variability across the studied characteristics, highlighting the diversity present within these collections and their potential for further research and utilization. The analysis of star apple collections revealed significant variation in morphological traits and fruit yield. Collection 09 emerged as the best performer with the tallest tree height (7.48 m) and the highest fruit yield per tree (24.98 kg). It also recorded the largest fruit weight (246.95 g) and the longest fruit length (8.82 cm), making it ideal for high-yield purposes. In contrast, Collection 08, though having a shorter tree height (4.72 m), stood out for its extended shelf life (6.89 days), highlighting its potential for storage and marketability. Other morphological parameters, such as inflorescence length and flower density, varied across collections, with Collection 02 having the longest inflorescence (1.39 cm) and Collection 01 exhibiting the maximum number of flowers per inflorescence (30.76). In terms of biochemical traits, Collection 06 excelled with the highest antioxidant capacity (18.22 AA mg/100 g), total sugar content (15.13 per cent), and phenolic content (2.87 mg/g), making it a valuable choice for health-oriented applications. Collection 08 showed the highest TSS (19.65 °Brix) and protein content (2.83 mg/g), indicating superior fruit quality. Meanwhile, Collection 07 had the highest acidity (0.10267 per cent), which could contribute to its unique flavor profile. These biochemical differences highlight the diverse nutritional potential of the collections. Physiological traits also showed marked differences, with Collection 08 leading in leaf sugar (28.37 mg/g), leaf protein (26.07 mg/g), and membrane stability index (80.75 per cent), suggesting better stress tolerance and overall vigor. However, Collection 01 displayed the highest relative water content (66 per cent), which is critical for maintaining hydration under varying environmental conditions. These findings underline the importance of both biochemical and physiological traits in identifying superior genotypes, with Collections 09, 08, and 06 standing out as the most promising for further cultivation and improvement. Anatomical studies on the fruit stalks of star apple accessions revealed that stalk characteristics influence fruit size. Longer stalks, such as in Collection 07 (21.01 mm), do not necessarily result in larger fruits, as seen with a fruit size of 55.42 mm. However, thicker stalks, like in Collection 06 (6.9 mm), were associated with larger fruits, measuring 68.3 mm. This highlights the importance of stalk diameter over length in supporting fruit size. Future research on abiu and star apple should focus on molecular characterization of genotypes to identify key genetic markers and traits influencing their superior performance. Multilocation trials across diverse environments should be conducted to understand their climate adaptability and ensure consistent productivity. As both crops are sexually propagated, variability and the lack of uniform planting materials remain significant challenges. Developing and distributing high-quality planting materials will play a crucial role in promoting these crops. Abiu and star apple are not only promising fruit crops for the future but also highly nutritious, rich in antioxidants, and beneficial for health. Their antioxidant properties can combat oxidative stress, contributing to better health outcomes, while their unique taste and texture make them appealing to consumers. These novel fruit crops are also essential for enhancing biodiversity, offering opportunities to diversify farming systems and reduce dependency on traditional fruit crops. By introducing these underutilized species into cultivation, we can increase genetic diversity, support ecological balance, and create new market opportunities for sustainable agriculture. Their potential to combine health benefits, biodiversity enhancement, and consumer appeal positions them as key crops for future agricultural development.
Role of biostimulants on growth and yield of papaya(Carica papaya L.)
(Department of Fruit Science, College of Agriculture , Vellanikkara, 2024-02-09) Anjana Mukesh; Aswini, A
Papaya (Carica papaya L.) is a most important fruit crop cultivated throughout the tropical and subtropical regions. The fruit is known for its sweet and musky flavour, making it a popular choice among the consumers. Papaya is rich in vitamins, particularly vitamins C, A and E. It contains enzymes called papain, which aids in digestion and is used for industrial purposes. The fruit is a good source of dietary fibre and antioxidants, contributing to overall health. The fruit's qualities and health benefits make papaya more appealing to customers. Drastic invasion of pests and diseases and scarcity of superior variety with higher yield are the major constrain for the economic production of papaya in Kerala. The uses of biostimulants on different horticultural and agronomic crops were gaining popularity due to their growth and development, quality enhancement and resilience to stress. In this background, the present study investigates on “Role of biostimulants on growth and yield of papaya (Carica papaya L.)” to evaluate its effect on the papaya variety “CO 7”. he biostimulants were applied every month and the observations were recorded at bimonthly intervals. Results indicated that significant variations were observed among treatments in various growth parameters. For instance, T2, involving chitosan and Sampoorna KAU Multimix, exhibited the minimum plant height at 120.47 cm and the plant collar girth was notably reduced (38.88 cm) after 10 months of growth in proportion to height. The application of biostimulants, especially chitosan and Sampoorna KAU Multimix (T2), significantly increased the number of leaves (23.44). In terms of flowering dynamics, significant differences were observed among treatments, with the earliest flowering in T2 at 108.77 days. Sex reversal were observed during the study encompassing male, female, bisexual and andromonoecious plants. The number of flowers per cluster reached its maximum in T1 (chitosan) at 4.97, while T2 demonstrated the highest fruit set percentage at 75.38%. The period from fruit set to maturity was notably shorter (131.61 days) and more number of days (6.72 days) for maturity to ripening reported in T2. Fruit parameters, including weight, length, girth, and volume, showed statistically significant differences among treatments, with T2 consistently recording the maximum values (1463.22 g, 24.32 cm, 40.95 cm, and 1283.33 cm3, respectively). Flesh thickness, fruit count and seeds per fruit also exhibited significant variations among treatments. Biochemical analyses further revealed distinct profiles. T2 demonstrated the highest total soluble solids at 14.11°Brix, while titratable acidity values were notably lower in T2, T1 and T4. T2 also showcased the highest total carotenoid content at 2.73 mg/100g, ascorbic acid content at 66.41 mg/100g and total sugar content at 11.81%. Shelf life was significantly longer in T2 at 8.61 days. Organoleptic evaluation scored the highest rank in T2 based on its overall appeal. Throughout the cropping period, the occurrence of diseases such as foot rot, Corynespore leaf spot, and viral infections in papaya crops was noted, showing no apparent relationship with the treatments applied in the current study. The application of chitosan has been associated with a reduction in viral diseases, as reported in earlier research works. However, to deepen our understanding and establish the potential of chitosan in mitigating viral diseases in papaya crops, further studies are imperative. In conclusion, the study highlights the superiority of the papaya variety CO 7, attributed to its impressive combination of high yield and superior fruit quality. Moreover, the application of biostimulants has proven to be instrumental in enhancing the overall growth, yield and quality of the papaya fruits. Notably, the efficient combination of Chitosan and Sampoorna KAU Multimix can give as a single spray, rather than separate spraying will reduce the labour cost. The application of combination of chitosan and Sampoorna KAU Multimix emerges as particularly promising, showcasing the potential to deliver higher economic benefits to farmers. The positive effects of Sampoorna KAU Multimix pave a way to standardize micro nutrient mixture for papaya as similar as practices established for banana. This finding current study underscores the importance of strategic biostimulant use in optimizing papaya production, offering valuable insight into agricultural practices aimed at improving crop outcomes, stress tolerance and economic returns.
Standardisation of fertigation and evaluation of chitosan as a bio stimulant on the biochemical and morphological traits of seedless watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai]
(Department of Vegetable Science, College of Agriculture , Vellanikkara, 2023-03-13) Jayalakshmi, T; Aswini, A
Watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] is a popular dessert vegetable of the Cucurbitaceae family. Even though the demand for fruit is very high, watermelon production confines to a limited area of 100 hectares with a production of 840 metric tonnes in Kerala. Precision farming is gaining importance in vegetable production and fertigation is an integral part of it. Watermelon responds well to fertigation in terms of growth and yield enhancement at different stages of crop like establishment phase, vegetative phase, flower initiation and at the time of harvesting. Erratic rainfall is the main limiting factor for watermelon cultivation in southern Kerala. Chitosan as a bio stimulant has a potential role in improving yield, quality, biotic and abiotic stress resistance of agricultural crops which can be exploited in the production of watermelon also. Researchers reported that bio stimulant effect of chitosan on plants was not much clear and it might be due to the increased photosynthetic rate by its application. Hence the present study was undertaken with an objective to standardise fertigation and to evaluate the effect of chitosan on biochemical and morphological characters of triploid seedless watermelon hybrid, Shonima from December 2021 to March 2022 at the Department of Vegetable Science. The experiment was conducted in split plot design with four levels of fertigation (50 % RDF, 75 % RDF, 100 % RDF and 125 % RDF) in main plots and three chitosan concentrations as foliar application (0.1 %, 0.2 % and 0.3 %) in subplots. Control was maintained with a level of fertilizer application @ 70: 25: 25 kg NPK/ha (KAU POP) and without any foliar application of chitosan. Fertigation was scheduled at three days interval and foliar application of chitosan was done at the pre flowering and fruit setting stages. Weather parameters like maximum temperature, minimum temperature, relative humidity and rainfall were recorded. As the crop duration during the summer season was shortened from 120 days to 90 days, only 25 splits of fertigation (6, 12, 7 during establishment, vegetative and fruiting stages respectively) were completed out of 40 (6, 12, 22 during establishment, vegetative and fruiting stages respectively). Fertigation doses given were 21.87: 15.62: 37.5 kg NPK/ha (50% RDF), 32.81: 23.44: 56.25 kg NPK/ha (75 % RDF), 43.75: 31.25: 75 kg NPK/ha (100% RDF) and 54.68: 39.06: 93.75 kg NPK/ha (125 % RDF). Fertigation levels significantly influenced vegetative and floral characters of watermelon. Longest vine length (3.87m) was recorded by 125% RDF. Male flower anthesis (24.39 days) was found to be early in 50 % RDF. Fruit and yield characters along with quality parameters were significantly influenced by fertigation doses. 100% RDF recorded maximum equatorial diameter (16.90 cm), polar diameter (17.55 cm), fruits/plant (4.52), average fruit weight (1.61 kg), yield/plant (5.97 kg/plant) and lycopene content (5.76 mg/100g). Maximum TSS (8.64°Brix) was recorded in 75 % RDF and maximum total sugar (5.38%) in 50 % RDF which was on par with 75 % and 100 % RDF. Chitosan concentrations influenced fruit, yield and quality parameters of watermelon. Foliar application of 0.1 % chitosan recorded maximum fruit equatorial diameter (16.76 cm), polar diameter (17.43 cm), fruits/plant (4.25), average fruit weight (1.94 kg), yield/plant (6.23 kg/plant), TSS (8.87 °Brix), lycopene content (4.96 mg/100g), reducing sugar (3.54 %) and total sugar content (5.38 %). 50% RDF recorded lowest rind thickness (1.17 cm). Interaction effect of fertigation doses and chitosan concentrations on fruit and yield characters and quality parameters was found to be significant. Treatment combination of 100 % RDF + 0.1 % chitosan spray recorded maximum equatorial diameter (18.08 cm), polar diameter (18.87 cm), average fruit weight (2.38 kg), yield/plant (8.06 kg/plant) and lycopene content (6.72 mg/100g). Maximum TSS (9.46 °Brix) and reducing sugar (3.98 %) was recorded by 75 % RDF + 0.1 % chitosan spray. Maximum total sugar content (5.67 %) was observed by 50 % RDF + 0.1 % chitosan spray. BC ratio (2.01) was found to be maximum with 100 % RDF + 0.1 % chitosan. Soil nutrient status was increased after the crop duration. Vulnerability index of watermelon bud necrosis virus, percentage disease index (PDI) of fusarium wilt and gummy stem blight reduced after foliar application of chitosan. The crop duration was reduced during the summer season hence, the recommended dose of fertigation for Shonima (90 days duration) was 43.75: 31.25: 75 kg NPK/ha. The recommended chitosan concentration was 0.1 % and treatment combination 100 % RDF + 0.1 % chitosan was found to the best for yield and quality parameters of watermelon. Fertigation enhanced the nutrient uptake thereby improved the growth, yield and quality of watermelon. Chitosan having potential role in biotic stress tolerance by regulating the jasmonic acid responsible for this by generating hydrogen peroxide. Enhanced yield and quality of fruits with foliar application of chitosan could be studied further with reference to physiological aspects like photosynthetic rate, stomatal conductance, transpiration rate etc. Biochemical and morphological traits of seedless watermelon was improved with influence of fertigation and foliar application of chitosan compared to conventional method of fertilizer application without any foliar spray of chitosan.
Standardisation of fertigation and evaluation of chitosan as a bio stimulant on the biochemical and morphological traits of seedless watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai]
(Department of Vegetable Science, College of Agriculture, Vellanikkara, 2023-03-13) Jayalakshmi, T; Aswini, A
Watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] is a popular dessert vegetable of the Cucurbitaceae family. Even though the demand for fruit is very high, watermelon production confines to a limited area of 100 hectares with a production of 840 metric tonnes in Kerala. Precision farming is gaining importance in vegetable production and fertigation is an integral part of it. Watermelon responds well to fertigation in terms of growth and yield enhancement at different stages of crop like establishment phase, vegetative phase, flower initiation and at the time of harvesting. Erratic rainfall is the main limiting factor for watermelon cultivation in southern Kerala. Chitosan as a bio stimulant has a potential role in improving yield, quality, biotic and abiotic stress resistance of agricultural crops which can be exploited in the production of watermelon also. Researchers reported that bio stimulant effect of chitosan on plants was not much clear and it might be due to the increased photosynthetic rate by its application. Hence the present study was undertaken with an objective to standardise fertigation and to evaluate the effect of chitosan on biochemical and morphological characters of triploid seedless watermelon hybrid, Shonima from December 2021 to March 2022 at the Department of Vegetable Science. The experiment was conducted in split plot design with four levels of fertigation (50 % RDF, 75 % RDF, 100 % RDF and 125 % RDF) in main plots and three chitosan concentrations as foliar application (0.1 %, 0.2 % and 0.3 %) in subplots. Control was maintained with a level of fertilizer application @ 70: 25: 25 kg NPK/ha (KAU POP) and without any foliar application of chitosan. Fertigation was scheduled at three days interval and foliar application of chitosan was done at the pre flowering and fruit setting stages. Weather parameters like maximum temperature, minimum temperature, relative humidity and rainfall were recorded. As the crop duration during the summer season was shortened from 120 days to 90 days, only 25 splits of fertigation (6, 12, 7 during establishment, vegetative and fruiting stages respectively) were completed out of 40 (6, 12, 22 during establishment, vegetative and fruiting stages respectively). Fertigation doses given were 21.87: 15.62: 37.5 kg NPK/ha (50% RDF), 32.81: 23.44: 56.25 kg NPK/ha (75 % RDF), 43.75: 31.25: 75 kg NPK/ha (100% RDF) and 54.68: 39.06: 93.75 kg NPK/ha (125 % RDF). Fertigation levels significantly influenced vegetative and floral characters of watermelon. Longest vine length (3.87m) was recorded by 125% RDF. Male flower anthesis (24.39 days) was found to be early in 50 % RDF. Fruit and yield characters along with quality parameters were significantly influenced by fertigation doses. 100% RDF recorded maximum equatorial diameter (16.90 cm), polar diameter (17.55 cm), fruits/plant (4.52), average fruit weight (1.61 kg), yield/plant (5.97 kg/plant) and lycopene content (5.76 mg/100g). Maximum TSS (8.64°Brix) was recorded in 75 % RDF and maximum total sugar (5.38%) in 50 % RDF which was on par with 75 % and 100 % RDF. Chitosan concentrations influenced fruit, yield and quality parameters of watermelon. Foliar application of 0.1 % chitosan recorded maximum fruit equatorial diameter (16.76 cm), polar diameter (17.43 cm), fruits/plant (4.25), average fruit weight (1.94 kg), yield/plant (6.23 kg/plant), TSS (8.87 °Brix), lycopene content (4.96 mg/100g), reducing sugar (3.54 %) and total sugar content (5.38 %). 50% RDF recorded lowest rind thickness (1.17 cm). Interaction effect of fertigation doses and chitosan concentrations on fruit and yield characters and quality parameters was found to be significant. Treatment combination of 100 % RDF + 0.1 % chitosan spray recorded maximum equatorial diameter (18.08 cm), polar diameter (18.87 cm), average fruit weight (2.38 kg), yield/plant (8.06 kg/plant) and lycopene content (6.72 mg/100g). Maximum TSS (9.46 °Brix) and reducing sugar (3.98 %) was recorded by 75 % RDF + 0.1 % chitosan spray. Maximum total sugar content (5.67 %) was observed by 50 % RDF + 0.1 % chitosan spray. BC ratio (2.01) was found to be maximum with 100 % RDF + 0.1 % chitosan. Soil nutrient status was increased after the crop duration. Vulnerability index of watermelon bud necrosis virus, percentage disease index (PDI) of fusarium wilt and gummy stem blight reduced after foliar application of chitosan. The crop duration was reduced during the summer season hence, the recommended dose of fertigation for Shonima (90 days duration) was 43.75: 31.25: 75 kg NPK/ha. The recommended chitosan concentration was 0.1 % and treatment combination 100 % RDF + 0.1 % chitosan was found to the best for yield and quality parameters of watermelon. Fertigation enhanced the nutrient uptake thereby improved the growth, yield and quality of watermelon. Chitosan having potential role in biotic stress tolerance by regulating the jasmonic acid responsible for this by generating hydrogen peroxide. Enhanced yield and quality of fruits with foliar application of chitosan could be studied further with reference to physiological aspects like photosynthetic rate, stomatal conductance, transpiration rate etc. Biochemical and morphological traits of seedless watermelon was improved with influence of fertigation and foliar application of chitosan compared to conventional method of fertilizer application without any foliar spray of chitosan.
Standardization of vegetative propagation techniques in dragon fruit( Hylocereus spp.)
(Department of Fruit Science, College of Agriculture , Vellanikkara, 2023-02-02) Mohammed Billal, M.; Aswini, A
Dragon fruit which belong to the family Cactaceae is commonly referred to as Pitaya, Pithaya, Queen of the Night, Night blooming Cereus. It is one among the exotic fruits, cultivated primarily for its attractive and highly nutritious fruit. It is native to Costa Rica, Guatemala and Southern Mexico, and are primarily found in tropical and subtropical regions. Though this can be easily multiplied through seeds, seedlings are not preferred as they have a long pre-bearing age and also not true to type in nature. Among the vegetative propagation methods, cuttings alone are used for mass multiplication of planting materials all over the world, whereas layering, grafting and budding are not in commercial use. Hence, the present study entitled “Standardisation of vegetative propagation techniques in dragon fruit (Hylocereus spp.)” was carried out in the Department of Fruit Science during 2022-2023, comprising three experiments: standardisation of length of rooted cuttings for propagation, standardisation of propagation by air layering and standardisation of propagation by grafting with the objective of evaluation of different vegetative propagation methods in dragon fruit. In the first experiment, the performance of different length of rooted cuttings were evaluated. Rooted cuttings of 120 cm length (T4) were found to be the best as it produced the maximum number of segments (13.10), number of newly emerged segments (3.70), number of spine areoles (556.00), number of roots (14.00), longest root (52.50 cm), duration of flowering (107.80 days), number of fruits (19.2 fruits/pole) and fruit yield (4.96 kg/pole). Flower and fruit morphology did not exhibit any significant variation with the treatments, as the same variety (“Cambodian Red” – red fleshed variety) was used for the study, and the flowering and fruiting characters are associated with the genetic nature of the variety. In the second experiment, the different rooting media for air layering were evaluated. Coirpith compost (25.00 days) and Arbuscular Mycorrhizal Fungi (AMF) with perlite and vermiculite (26.50 days) recorded the minimum number of days for root emergence. Sphagnum moss recorded the maximum number of adventitious roots per air layer (15.30). Longest roots were observed in AMF with perlite and vermiculite (11.04 cm) and sphagnum moss (10.85 cm) and were found to be on par with each other. The AMF with perlite and vermiculite (5.45 mm) and sphagnum moss (5.38 mm) recorded maximum root diameter. In terms of survival percentage, sphagnum moss recorded the highest survival percentage of 81.25%. Sawdust (3.33 air layers) and sphagnum moss (3.25 air layers) produced the maximum number of rooted air layers after 90 days of air layering. In the third experiment, different grafting methods were evaluated with two varieties of dragon fruit, Mexican Red and Malaysian Red. When Mexican Red was used as the rootstock, horizontal grafting (T1) (16.00 days), shoot grafting (T3) (18.50 days) and seedling grafting (T6) (18.80 days) recorded the minimum number of days taken for sprouting. Horizontal grafting recorded the maximum number of segments (2.00). V-cut bud grafting (T5) and seedling grafting (T6) did not produce any segments. Shoot grafting recorded the longest segments (101.80 cm) and maximum survival percentage (100%). The girth of the rootstock did not vary in both the rootstocks. The maximum girth of the scion (135.20 mm), maximum scion length (117.40 cm) and taller grafts (158.40 cm) were observed in shoot grafting. When Malaysian Red was used as the rootstock, the minimum number of days for sprouting were recorded for seedling grafting (15.75 days) and horizontal grafting (16.20 days). Bone grafting (T4) (1.40), horizontal grafting (1.33) and shoot grafting (1.33) recorded the maximum number of segments. Horizontal grafting produced the longest segments (115.50 cm). Shoot grafting and L-grafting recorded the maximum survival percentage (100%). The maximum girth of the scion was observed in shoot grafting (148.50 mm). The length of the scion was the maximum for horizontal grafting (T1) (131.30 cm) and shoot grafting (T3) (116.50 cm). Both horizontal grafting (165.10 cm) and shoot grafting (158.80 cm) produced taller grafts. Initially, the success percentage was the highest in horizontal grafted plants thereafter shoot grafting recorded the highest percentage throughout the study when Mexican Red was used as the rootstock. When Malaysian Red was used as the rootstock horizontal grafting recorded the highest success percentage at 15 days after grafting. But, 30 to 75 days after grafting shoot grafting recorded the highest percentage. Finally, shoot grafting and L-grafting were found to be the best with maximum success percentage. The percentage of graft establishment was highest in shoot grafting at 30, 60 and 90 days after grafting when both rootstocks were used. Additionally, L-grafting recorded the highest graft establishment at 90 days after grafting when Malaysian Red was used as the rootstock. The method of V-cut bud grafting (T5) was considered as a failure one with no success percentage. The present research revealed that using 120 cm long rooted cuttings (T4) (4 feet) is the most suitable planting material for dragon fruit in order to produce the highest yield, longest fruiting period, the largest number of fruits and significant improvement in vegetative characteristics. Sphagnum moss (T3) was found to be the most effective rooting medium for air layering in dragon fruit due to its higher success rate. The best grafting technique for dragon fruit was found to be shoot grafting (T3), which produced maximum scion girth, scion length, graft height and success percentage.