Evaluation of per se performance of parents and F₁ hybrids for yield and quantitative traits in pumpkin (Cucurbita moschata L.)

Introduction

Pumpkin (Cucurbita moschata Duch. ex Poir.) is a major cucurbitaceous vegetable crop grown in tropical and subtropical locations across the world. It is a member of the Cucurbitaceae family (2n = 2x = 40) and is widely produced because to its high production, great storage quality, capacity to adapt to a variety of agroclimatic conditions, and several culinary and nutritional purposes (Robinson and Decker-Walters, 1997) [12] . An commercially significant vegetable crop, pumpkin is widely grown in Asia, Africa, Europe, and the Americas. In India, it is grown during both rainy and summer seasons and contributes significantly to vegetable production due to its wide consumer acceptance and high market demand (Choudhury, 1996) [2] . It is well known that pumpkin fruits are a great source of bioactive compounds, vitamins, minerals, dietary fiber, and carbs. Along with vitamin C, vitamin E, potassium, calcium, phosphorus, and antioxidant chemicals that support human health, the fruit is especially rich in β-carotene, a crucial precursor of vitamin A (Paris, 2016) [11] . Pumpkin is a nutritionally exceptional vegetable crop, and the seeds are similarly useful since they include high-quality edible oil, proteins, unsaturated fatty acids, tocopherols, phytosterols, and various minerals (Kulczyński and Gramza-Michałowska, 2019) [7] . Pumpkin has become more and more important in the food processing sectors for the creation of soups, baked goods, infant meals, drinks, and nutraceutical items due to its high nutritional content and functional food value (Omar et al., 2024) [9] . Despite its economic significance, pumpkin yield is still relatively low in many growing locations because local cultivars are genetically diverse, there are no better hybrids, and the genetic variability that is present is not fully used. Therefore, finding and using genetically superior parents and hybrids with desirable agronomic features is crucial for increasing yield and fruit quality. The selection of prospective breeding materials for agricultural improvement programs is based on the evaluation of parental genotypes and hybrids under field settings, which yields important information on their performance and adaptability (Acquaah, 2020) [1] . Since per se performance directly reflects the phenotypic expression of economically significant features under a particular environment, it is regarded as one of the most trustworthy criteria for assessing the genetic potential of parental lines and hybrids. Before they are used in breeding programs or suggested for commercial cultivation, breeders can discover top genotypes with greater production potential, fruit quality, and adaptability by evaluating per se performance. Superior per se performance of hybrids generally results from the favourable interaction of genes inherited from genetically diverse parents and is often reflected in enhanced vegetative growth, improved flowering behaviour, increased fruit set, larger fruit size, and higher fruit yield (Falconer and Mackay, 1996) [3] . Therefore, a crucial stage in hybrid breeding programs aiming at creating high-yielding cultivars is the rigorous assessment of parental lines and F₁ hybrids. There is a lot of genetic diversity that can be successfully utilized through selection and hybridization, according to earlier research that showed significant variation among pumpkin genotypes for yield and related traits (Mohanty, 2000; Pandey et al., 2010; Tamil Selvi et al., 2013) [8,10,13] . Finding high-performing parental genotypes and F₁ hybrids suited to the agroclimatic conditions in northwest India is still a challenge, despite the fact that many research have examined hybrid performance in pumpkin. Additionally, assessing recently created hybrids for a variety of quantitative and yield-related characteristics is crucial for finding promising genotypes appropriate for both commercial production and future breeding initiatives. A thorough evaluation of per se performance helps breeders choose better genetic resources for creating better pumpkin cultivars and offers important information on the productive potential of individual parents and hybrids. Therefore, the present investigation was undertaken to evaluate the Per se performance of fourteen parental genotypes and forty F₁ hybrids of pumpkin for nineteen quantitative and yield-related traits under field conditions. The study aimed to identify superior parental lines and promising hybrids exhibiting desirable agronomic performance and high yield potential for their effective utilization in future pumpkin improvement programmes.

Materials and Methods

Experimental site

The field experiment was conducted during the summer season of 2022-23 and 2023-24 respectivelyat the Horticulture Research Centre, Department of Vegetable Science, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh, India. The experimental site is situated at 29°01′ N latitude and 77.75° E longitude, at an elevation of approximately 297 m above mean sea level, representing the North Western Plain Zone of Uttar Pradesh.

Experimental materials

The experimental material consisted of fourteen genetically diverse pumpkin genotypes maintained at the Horticulture Research Centre of the university. These included ten lines, namely Kashi Harit, Pumpkin 21-81, VRPK-310, Narendra Agrim, Pumpkin-303, Pumpkin-87, Pumpkin-73, Pumpkin V-4, Pumpkin LM-350 and VRPK-07-01; and four testers, namely Pusa Vikas, Arka Suryamukhi, Arka Chandan and Azad Pumpkin. Forty F₁ hybrids were developed by crossing the ten lines with the four testers in a line × tester mating design during the preceding season. Thus, a total of fifty-four genotypes (14 parents + 40 F₁ hybrids) were evaluated in the present study.

Experimental design

The experiment was laid out in a Randomized Block Design (RBD) with three replications. Each replication contained all fifty-four genotypes, and the entries were randomized separately within each replication. The field was prepared to a fine tilth by repeated ploughing, harrowing, and planking. Well-decomposed farmyard manure at the rate of 20 t ha⁻¹ was incorporated into the soil during field preparation. Fertilizers were applied at the recommended dose of 100:60:80 kg N:P₂O₅: K₂O ha⁻¹. Half of the nitrogen along with the full doses of phosphorus and potassium was applied as basal, while the remaining nitrogen was top-dressed 30 days after sowing. Seeds were soaked in water for 24 h prior to sowing to ensure uniform germination. After shade drying, the seeds were sown in well-prepared plots at a spacing of 3.0 m × 1.0 m and at a depth of approximately 2-3 cm. Standard agronomic practices including irrigation, weeding, hoeing, and plant protection measures were adopted uniformly for all treatments throughout the crop growth period.

Observations recorded

Observations were recorded on five randomly selected plants from each genotype in each replication for nineteen quantitative and yield-related traits, namely vine length, number of primary branches, days to first male and female flower initiation, number of male and female flowers per vine, sex ratio, fruit weight, fruit length, fruit diameter, fruit flesh thickness, days to first fruit set, number of fruits per plant, number of seeds per fruit, 100-seed weight, fruit yield per plant, days to first fruit harvest, total soluble solids (TSS) and total fruit yield per hectare. Fruit weight was recorded using a digital balance, while fruit length, fruit diameter, and flesh thickness were measured using standard measuring instruments. TSS was determined from fresh fruit juice using a digital refractometer and expressed in °Brix. Total yield per hectare was calculated from fruit yield per plant and converted into tonnes per hectare.

Statistical analysis

The recorded data were subjected to analysis of variance (ANOVA) appropriate for the Randomized Block Design as described by Panse and Sukhatme (1969). The significance of differences among genotypes was tested using the F-test at 5% and 1% probability levels. When significant differences were observed, treatment means were compared using the Critical Difference (CD) at the 5% level of significance.

Results and Discussion

Analysis of variance

The analysis of variance revealed highly significant differences among the evaluated genotypes for all nineteen quantitative characters, indicating the existence of considerable genetic variability among the parental lines and F₁ hybrids. The observed variability among genotypes indicated that the parental lines used in the hybridization programme were genetically diverse and produced hybrids with a wide range of phenotypic expressions. Similar observations regarding the existence of substantial variability among pumpkin genotypes have been reported by Mohanty (2000) [1] , Tamil Selvi et al. (2013) [13] , Hatwal et al. (2018) [5] , Ikbal et al. (2022) [6] and Harshini et al. (2024) [4] .

Per se performance of parents

The fourteen parental genotypes exhibited considerable variation for all quantitative characters, reflecting their diverse genetic background. Such variation among the parents is advantageous for selecting suitable donor lines for hybrid development and future breeding programmes. Among the parental lines, Pumpkin-87 emerged as the most promising genotype for fruit yield and associated characters. It recorded the highest fruit yield per plant (26.81 kg) and one of the highest total yields (35.94 t ha⁻¹). In addition, it produced the maximum number of primary branches (7.12), the highest number of female flowers per vine (8.70), desirable fruit weight (3.25 kg), and a higher number of fruits per plant (8.25), indicating its excellent yield potential. Pumpkin V-4 also performed remarkably well, producing a total yield of 35.95 t ha⁻¹ with comparatively higher fruit yield per plant (21.56 kg), greater number of fruits per plant (6.25), and desirable fruit weight (3.45 kg). Similarly, Pumpkin-73 exhibited superior performance for fruit yield per plant (20.59 kg) and total yield (35.43 t ha⁻¹), together with relatively high fruit weight (4.16 kg) and a higher number of fruits per plant (4.95). Among the remaining parental lines, Pumpkin-303 recorded the highest fruit yield per plant (17.67 kg) among mediumyielding parents and exhibited comparatively larger fruit size with fruit weight of 3.24 kg. VRPK-310 was another superior parent, producing fruit yield per plant of 14.55 kg and total yield of 23.43 t ha⁻¹. It also possessed desirable vine length (9.65 m), fruit weight (3.13 kg), fruit length (21.95 cm), and fruit diameter (12.67 cm), indicating its usefulness as a productive breeding parent.

Among the testers, Arka Suryamukhi performed better than the other testers, recording fruit yield per plant of 14.09 kg and total yield of 23.49 t ha⁻¹. The tester also produced comparatively thicker fruit flesh (3.65 cm), higher TSS (10.65 °Brix), and a greater number of seeds per fruit (185.32). Pusa Vikas showed desirable fruit weight (1.26 kg) and produced the highest number of fruits per plant (4.06) among the testers, whereas Arka Chandan was superior for fruit diameter (12.78 cm) and TSS (9.40 °Brix). The variability observed among the parental genotypes clearly demonstrated the presence of diverse agronomic characteristics, thereby providing an excellent opportunity for selecting elite parents possessing complementary traits. Parents such as Pumpkin-87, Pumpkin V-4, Pumpkin-73, Pumpkin-303, VRPK-310, and Arka Suryamukhi exhibited superior performance for yield and its component traits and may therefore serve as valuable genetic resources for future pumpkin breeding programmes.

Per se performance of F₁ hybrids

The forty F₁ hybrids exhibited wide variation for all quantitative and yield-related characters, demonstrating the effectiveness of hybridization in generating superior recombinants. Several hybrids significantly outperformed their respective parents for fruit yield and associated traits, indicating the potential of these cross combinations for commercial exploitation. Among all the hybrids, Arka Suryamukhi × Pumpkin-73 recorded the highest total yield (52.93 t ha⁻¹) along with the highest fruit yield per plant (28.77 kg), making it the most promising hybrid in the present investigation. The superior performance of this hybrid was mainly attributed to its favourable expression for fruit weight, number of fruits per plant, and other yield-contributing characters. The hybrid Pusa Vikas × VRPK-310 ranked second with a total yield of 52.08 t ha⁻¹ and exhibited excellent fruit yield per plant together with desirable fruit size and fruit weight. Similarly, Arka Suryamukhi × Pumpkin LM-350 recorded a total yield of 43.88 t ha⁻¹, while Azad Pumpkin × Pumpkin-87 produced 43.41 t ha⁻¹. Another promising hybrid, Arka Suryamukhi × Narendra Agrim, recorded a total yield of 41.83 t ha⁻¹ and showed superior performance for several yield-attributing traits. These hybrids may therefore be considered promising candidates for multilocation evaluation and possible commercial cultivation. The superior performance of these hybrids may be attributed to the favourable combination of genes inherited from genetically diverse parents, resulting in better vegetative growth, efficient flowering, increased fruit set, larger fruit size, and ultimately higher fruit yield. Similar findings have been reported by Tamil Selvi et al. (2013) [13] , Hatwal et al. (2018) [5] , Ikbal et al. (2022) [6] , and Harshini et al. (2024) [4] , who also observed substantial variation in the performance of pumpkin hybrids and identified several high-yielding cross combinations.

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