Performance of Some Soybean Genotypes (Glycine max L.) to Germination and Seedling Characters as Affected by Planting Dates and Phosphorus Fertilization

To investigate the performance of some sunflower genotypes to phosphorus fertilizer rates and planting dates to germination characters and seedling parameters. A laboratory experiment accompanied in seed lab during April and May 2017.The experiments included six sowing dates at 1th May, 15th May and 31th May, three soybean cultivars namely Crawford, Giza 22 and Giza 111 and three rates of phosphorus fertilizer viz. 0, 37.2 and 74.4 kg P2O5/ha.The tallest shoot, great percentages of germination, the lowermostpercentagesof dead seedand the highestcoefficient of velocitypercentage from sown on mid-May. In addition, the lowest days of germination time was produced from sown on first May. Whereas, the tallest root, the highest weight of fresh shoot and root as well as shoot dry weight from sown on end-May.The results clearly revealed that the highest percentage of germination, soot length and root length obtained from sown cv. Giza 111. The uppermostenergy of germination, shoot and root dry weight were recorded from sown Giza 22 cultivar. In addition, sown Crawford cultivar produced the highestdead seedpercentage and the lowest mean germination time.The results indicated that the lowest mean germination time and maximum percentage of coefficient of velocity, tallest shoot and root, weight of fresh shoot, shoot and dry root were obtained fromfertilizationof phosphate at the rate of31 kgP2O5/fed. It summarized that seed Giza 111 cultivar recorded the best in seed viability when sown on first May and fertilized with phosphorus fertilizer at the rate of 74.4 kg P2O5/ha.

INTRODUCTION Soybean (Glycine max (L.) Merrl) is considered the most important oil crop in Egypt. To overcome the shortage of edible oil in Egypt, it could be achieved sown soybean at proper agronomic management, such as, sowing times of different soybean cultivars and phosphorus fertilizer rates and their effect on seed quality. The increase of seed production may attributed to agriculture management that could potentially improve seed viability.The JS-335 variety recorded the highest increase in germination percentage and seedling vigour index. Germination percentage, seedling vigour index and seedling dry weight decreased progressively as sowing delayed (Vidyapeeth, 2002). Sown at different dates affect seed productivity andcreatinga goodseed quality (Rahman et al., 2005). Sowing date is an important factor regulating soybean seed quality. G-2 cultivar had higher percentages of germination and seed vigour than cultivar PB-1 or BS-5 genotypes. The highest germination percentage and good vigour produced from all the cultivars on November and December sown.Whilst, sown in September increased germination percentage and seedling vigour during Kharif II. Sown during November to December in Rabi season and August to September in Kharif-II season produced the highest germination percentage (Rahman et  .Therefore, the goal of this research is aimed to investigate soybean seed cultivars viability as influenced by sowing date and phosphorus fertilization rates.

Research time and site:
The laboratory experiment intended to study the effect of three sowing dates at 1 th May, 15 th May and 31 th Mayfor three soybean cultivars (Crawford, Giza 22, Giza 111) under and three phosphorus fertilizer rates (0, 37.2 and 74.4 kg P2O5/ha)to germination and seedling parameters.Afactorial experiment in RCBD with four replicationwas used. The experiment includes three factors, the first three sowing date at 29 th April, 14 th May and 30 th May The second factor included three soybean cultivarsi.e.Crawford, Giza 22, Giza 111) from ARC, Ministry of agriculture, Egypt. The third cultivar includesthe three phosphorus fertilizer rates (0, 37.2 and 74.4 kg P2O5/ha. Twenty-five seeds of uniform size in each treatment for each cultivar allowed germinating on a filter paper in 9 cm diameter Petri dishes. Seeds were germinate in a germination chamber in 20-25 о C.Thus, the whole experiment comprised 108 Petri dishes. Each filter paper moistened with a distilled water according to ISTA Rules, 2016.

Studied Characters:
Soybean seed of both seasons subjected for determination of germination characters and seedling parameters in the laboratory experiment. Germination characterswere estimated as follows: MGT= ∑dn ÷∑ n 6-Percentage of dead seed = Number of dead seed /total number of seeds 7-Shoot length (cm)of five seedlings from the seed to the tip of the leaf blade was measured. 8-Root length (cm)of five seedlings from the seed to the tip of the root was measured. 9-Weight of the fresh shoot (g) of five seedling shoots was weighted. 10-Weight of fresh root (g)of five seedling roots was weighted. 11-Weight of dry shoot (mg)of five seedling shoots was weighted after oven dryingat 75 º C for 48 h. 12-Root dry weight (mg)of five seedling shoots was weighted after oven dryingat 75 º C for 48 h.

Experimental analysis:
Collected data, statistical analysis of variance technique using the MSTAT-C statistical package programmed as described by a procedure of Gomez and Gomez (1991). For comparisons between treatment means, the lest significant differences test (LSD) for 5 and 1 % level of probability was used according to Snedecor and Cochran (1980).

III. RESULTS AND DISCUSSIONS 3.1. Effect of sowing dates:
The outcomes that obtainable in Tables (1, 2 and 3) exposed that sown dates significantly affected germination anddead seedpercentage, mean germination time, andcoefficient of velocitypercentage, root length (cm), weight of shoot fresh (g), shoot dry weight (gm),root fresh weight (gm), except energy of germination percentage, shoot length (cm) androot dry weight (gm) insignificantly affected. The tallest shoot (highest percentage of germination (84.66 %), the lowest dead seedpercentage (15.33 %) and the highestcoefficient of velocitypercentage (30.07 5) from sown on mid-May. In addition, the lowest mean of germination time (2.2 day) was obtained from son early on first May. Whereas, the tallest root (6.21 cm), the highest weight of fresh shoot (0.72 g) and root (0.15 g) as well as shoot dry weight (0.18 g) from sown on end-May.Sown on 2 nd December maximized the percentage of germination and vigor index that recorded a good quality soybean seed (Kundu et al., 2016).

Performance of soybean cultivars:
Average of germination and energy of germination percentages and dead seedpercentage, mean germination time, andcoefficient of velocitypercentage, shoot length (cm), root length (cm), shoot fresh weight (gm), shoot and root dry weight (gm) significantly affected by studied soybean cultivars,except, coefficient of velocitypercentage, root and shoot fresh weight (gm) insignificantly influenced. The results clearly revealed that the highest percentage of germination (81.22 %), soot length (6.52 cm) and root length (6.26 cm) was recorded from sown Giza 111 cultivar. The highest energy of germination (43.25 %), shoot (0.16 g) and root (0.2 g) dry weight were recorded from sown Giza 22 cultivar. In addition, sown Crawford cultivar produced the highestdead seedpercentage (22.51 %) and the lowest mean germination time (2.6 day). The JS-335 variety recorded the highest increase in germination percentage and seedling vigour index. Germination percentage, seedling vigour index and seedling dry weight decreased progressively as sowing delayed (Vidyapeeth, 2002).

Effect of phosphorus fertilizer rates:
Average of mean germination time andcoefficient of velocitypercentage, shoot length (cm), root length (cm), shoot fresh weight (gm),shoot and root dry weight (gm) significantly affected due to different phosphate fertilization rates, except, germination and energy of germination and dead seedpercentage and root fresh weight (gm) insignificantly affected as shown in Tables (1  and 2). The results indicated that the lowest mean germination time (2.54 day)and maximum percentage of coefficient of velocity(30.5 %), tallest shoot (6.63 cm) and root (6.28 cm), shoot fresh weight (0.67 g), shoot (0.17 g) and root (0.03 g) were obtained fromfertilizationof phosphate at a rate of74.4 kg P2O5/ha.Fertilization with K, Zn, and P enhanced seed viability and seedling vigor (Sawan et al., 2011).Extreme in P and K fertilization rates can result in lower seed viability and vigor (Krueger et al.,  2013).

Interaction between sowing dates and soybean cultivars:
Means ofmean germination time,coefficient of velocitypercentage,shoot length (cm), weight of fresh shoot and root (g) significantly influenced by the interactiveamong sowing dates and soybean cultivars, and insignificantly influenced germination, energy of germination and dead seedpercentages, root length (cm), weight of dry shoot and root (g         Fig. 9. Average of root fresh weight (g)as influencedby interaction between sowing date and phosphate fertilization rates.

Interaction between soybean cultivars and phosphorus fertilizer rates:
Means ofgermination and dead seedpercentages,shoot and root length (cm), shoot fresh and dry weight (g)significantly affected by the interaction between soybean cultivars and phosphorus fertilizer ratesbut, insignificantly influenced mean germination time, energy of germination root fresh and dry weight (g).The results graphically illustrated in Figs. 10, 11, 12, 13, 14 and 15 clearly showed that highest % of germination (86.0 %), the lowest dead seed % (14.0 %), tallest shoot (7.1 cm) and root (7.0 cm), weight of fresh shoot (0.72g) and dry (0.19 g) were obtained from sown Giza 111 cultivar and phosphorus fertilization at the rate of74.4 kg P2O5/ha. However, the lowest values were recorded from sown Crawford cultivar and without phosphorus fertilization. Fig. 01. Average of germination % as influenced by the interactive among soybean cultivars and phosphate fertilization rates. Fig.11. Average of dead seed% as influenced by interaction among soybean cultivars and phosphate fertilization rates.

Interaction among sowing dates, soybean cultivars and phosphorus fertilizer rates:
Means of percentage of germination and energy of germination dead seed percentages, mean germination time, shoot and root length (cm), shoot fresh and dry weight (g),root fresh and dry weight (g) insignificantly affected by the interaction among sowing dates, soybean cultivars and phosphorus fertilizer rates.

IV. CONCLUSION
It could be concluded that seed Giza 111 cultivar recorded the best in seed viability when sown on first May and fertilized with phosphorus fertilizer at a rate of 74.4 kg P2O5/ha.