Effect of Seed Priming, Sowing methods and Bio-fertilizers on Yield and Yield Components of Seedy Watermelon (Citrullus Lanatus)

Watermelon (Citrullus Lanatus) is one of the most important fresh fruits in Iran particularly during summer. After China, in terms of production and cultivation area, Iran placed second in the world. Research conducted in different regions (especially in arid and semi-arid regions, like Iran) indicated that poor germination and establishment of seedlings in the field causes low yield, particularly in vegetables. Seed priming, (to increase the percentage and rate of germination) and transplanting to increase plant establishment and use of bio-fertilizers to increase food availability during the growing season are inevitable to transfer to ecological agriculture. The purpose of this research was to evaluate the effect of seeds osmopriming, transplanting and bio-fertilizers on watermelon grain yield.
This experiment was conducted at split plot based on complete block design with three replications in the Laboratory, Greenhouse and the Farm of the Faculty of Agriculture, Ferdowsi University of Mashhad in 2013. First factor was seed priming in two levels (unprimed and primed), the second factor was transplanting in two levels (direct sowing and transplantation) and the third factor was bio-fertilizers containing pseudomonas and Azotobacter in two levels (non bio-fertilizers and bio-fertilizers). Leaf area index (LAI), number of fruits per plant, number of seeds per fruit, 1000 seed weight, grain yield and total dry matter were determined.
Transplants produced using osmoprimed seeds that had been sprayed with bio-fertilizers on the field (T2P2K2) had higher LAI than the other treatments (Table 3). Bio-fertilizers in both transplanting and direct sowing produced more LAI, but osmopriming of seeds with PEG 6000 had little impact on LAI (Table 3). LAI is one of the growth parameters which had a great effect to achieve maximum yield that needs to be at higher level before flowering. Izadkhah et al. (2010) and Ghiasabadi (2012) reported that onion and corn leaf area and LAI 50 days after transplanting were higher than the direct sowing According to the results, osmoprimed seeds of watermelon, transplanting and bio-fertilizers and interactions of bio-fertilizers with osmopriming treatment had significant effect on the number of fruits per plant (Table 2). Osmopriming of seeds increased (8%) the number of fruits per plant compared to the control (unprimed seeds) (Table 4). The number of fruits per plant with grain yield (r= 0.63**) and total dry matter (r= 0.71**) had a significant correlation. Mature plants resulted from transplanting produced 2.9 fruits per plant, compared to direct sowing, with 2.5 fruits per plant (Table 4). Rahnama and Bakhshande (2005) reported that oilseed rape transplants produced higher numbers of pods per plant in compare with direct sowing. Primed seeds with application of bio-fertilizers caused an increase in the number of fruits per plant. Fertilizer treatments in the primed seeds, with 3.5 fruits, and primed seeds without fertilizer treatment, with 2.2 of fruits per plant, had the highest and lowest fruits per plant, respectively (table 5). Seed yield per plant is one of the most important economic indexes. The results showed that the effect of osmo-priming (at %5 level), transplanting, fertilizers and bio (at 1% level) and the triple interactions on grain yield (at 5% level) were significant (Table 2). As the results, osmo-priming of seeds, transplanting and fertilizer were superior compared to control treatments (table 4). In this study osmopriming, transplanting and bio-fertilizers increased grain yield up to 13%, 23% and 65%, respectively (Table 4).
Resowing generally is one of the major problems of farmers in direct sowing of seedy watermelon due to poor germinability and establishment, sowing at heavy soil, low rainfall, irrigation water shortages conditions or lack of ability to absorb water and fertilizers. Osmopriming with saving inputs will lead to an early and ultimately increase performance. To face this, transplanting using primed seeds alongside of application of organic fertilizers is recommended.