EFFECT OF PLANT DENSITY, SEED SIZE AND SEAWEED EXTRACT ON PRODUCTIVITY AND QUALITY OF SNAP BEAN SEEDS

Abstract

Two field experiments were conducted during the two growing summer seasons of 2013 and 2014 at the Experimental Farm of Vegetable Crops at Kaha, Qalyubia Governorate, Horticulture Research Institute, Agriculture Research Center(ARC), Egypt, in order to investigate the effect of seed size, plant density and foliar application with some algae extracts on vegetative growth, chemical composition, flowering characteristics andseed yield and its quality of snap bean cv. Valentino. Seed size,i.e., large, small and control (without grading), seeds were separated into two seed size classes by sieving through laboratory sieves (>4.76 mm for large seeds and > 4 mm for small seeds) and a randomseed sample, taken from cleaned seeds, not gradedand used as the control. Plant density at rate of 22 and 33 plants per m2 obtained by planting seeds at 7.5 and 5 cm apart on one side of the irrigation line, respectively. Foliar application with some algae extracts such as seaweed (Algost at 3 ml/ l), fresh water algae(spirulinaat 1 ml/ l), mixture of them(3 ml/ l of Algost+ 1 ml/ l of Spirulina) and control(sprayed with distilled water). Plants were sprayed three times during the growing seasons, the first was after 21 days from sowingand then two weeks intervals. A split–split plot design was used with three replications, where three seed sizes distributed randomly in the main plots and two plant population rates arranged in sub plots and foliar spray with algae extract treatments allocated in sub–sub plots. Results showed a clear enhancement of plant vegetative growth parameters, chlorophyll, N, P, K contents of leaves and seed yield quantity and quality by sowing large seeds compared with other seed sizes. Meanwhile, higher plant density at rate of 33 plants per m2 gave the highest values of plant length and seed yield per feddan, while the lower plant density at rate of 22 plants per m2gave the highest values of number of branches and leaves, leaf area as well as fresh and dry weight per plant, leaves chlorophyll and macro-elements (NPK)content, the percentage of fruit set and seed yield per plant as well as seed quality, on the other handthere were no significant differences in weight of 100 seeds between the two plant densities in both seasons. All foliar application with algae extracts significantly increased all the studied parametersof vegetative growth, seed yield and its quality compared to the control treatment. The best application was spray with the mixture between seaweedextract and fresh water algae extract together followed by spray with seaweed extract alone in the two seasons. The three-way interaction indicated that sowing large seeds with higher plant density at rate of 33 plants per m2 then spray plants with the mixture gave the highest significant increase in plant length and seed yield per feddan. Meanwhile,sowing large seeds with lower plant density at rate of 22 plants per m2 and spray with seaweed extract alone or mix with fresh water algae extract gave the highest significant increase in other studied parameters. Keywords: Snap bean, Plant density, Seed size, Foliar spray, Seaweed, Fresh water algae extract, Seed yield.