Ana Lúcia Pereira Kikuti

Procedures for evaluation of soybean seed vigor, including an automated computer imaging system

Seed coating has potential to become a strong factor in the seed sector. It allows farmers to add a vast variety of materials to the seed. This project had the objective of studying the effects of sources and doses of phosphorous added to the soybean seed by coating. It involved four doses of phytic acid and bicalcic phosphate, which were: 0.0; 0.7; 1.4 and 2.1g/100g seeds. The treatments were evaluated in two types of soil: high and low phosphorous availability, obtained from a soil with initial P content of 10.5 mg dm-3, in which in one type of soil 60kg ha-1 of super triple phosphate was applied while nothing was applied to correct the P content in the other soil. The polymer used in seed coating was applied at 0.8 ml/100g of seeds. A randomized complete block design was used with three replications. It was used vases with 12 L of capacity with three plants per experimental units. The following parameters were evaluated: number of seeds per plants, weight of seeds per plants and the weight of a thousand seeds.. It was concluded that seed coating of soybeans seeds with phosphorous increased productivity according to doses and phosphorous sources. The dosage of 21 grams of phytic acid per 1 kilo of seeds increased the yield by more than 14%.

Potencial fisiológico de sementes de couve-flor e desempenho das plantas em campo

This research studied the relationship of cauliflower seed physiological potential and plant field performance. Two experiments in subsequent years were conducted with six lots of cauliflower seeds, cultivar Sharon. Physiological potential was evaluated by germination (speed and percentage), seedling emergence, controlled deterioration, accelerated aging, electrical conductivity and potassium leachate tests. Comprised seedling and plant performance were evaluated by height, leaf number and dry weight, where as plant production was expressed by head diameter and yield; second experiment also included determination of replant percentage. Completely randomized design was utilized to laboratory tests and randomized block design for greenhouse and field tests with four replications each. Accelerated aging or controlled deterioration tests are indicated in combination with electrical conductivity or potassium leachate tests to identify the best performance cauliflower seed lots. Seed vigor level influenced plant initial growth, under large differences among seed lot physiological potential, but this effect did not persist over time aud and did not affect yield.

Condicionamento fisiológico de sementes de couve-flor

This research was conducted to define an adequate procedure for cauliflower seed priming and to verify whether the seed physiological potential affects priming results. Six seed lots, three of the cultivar Sharon and three of Teresopolis Gigante, were submitted to hydropriming between two, four and six sheets of towel paper and to osmopriming between four sheets of towel paper moistened with polietilenoglycol 6000 solutions (-0,1 and -0,2 MPa potentials). In all priming procedures, the seed water content was adjusted to 32% or 38% for cv. Sharon and 34% or 41%, for cv. Teresopolis Gigante seeds. The effects of treatments on germination and seedling emergence were compared to unprimed control. Results showed that hydropriming between four and six sheets of towel paper was efficient to favor speed of germination (VG) and speed of seedling emergence (VE) in both cultivars when seeds attained 38% (cultivar Sharon) and 41% (cultivar Teresopolis Gigante). VG increased from 14,6 (control) to 16,4 (hydroprimed seeds) in cv. Sharon seed lots of higher and lower physiological potential; the same for VE that incresead from 8,9 to 11,3 and from 7,8 to 11,6 in seed lots of lower physiological potential. In seeds of cv. Teresopolis Gigante, hydropriming promoted increases in the VG and VE, independently of seed physiological potencial; VG values ranged from 16,4 to 21,4 and the VE from 9,5 to 13,5. Results showed that hydropriming between four and six sheets of towel paper, in which seeds attained moisture content close to the required for primary root protrusion is efficient to favor the speed of germination and seedling emergence of cauliflower seeds; the influence of vigor level on seed priming response is closely related to cultivar and seed lot management.

Interferência da assepsia em sementes de pimentão submetidas ao teste de envelhecimento acelerado

The objective of this study was to assess the incidence of fungi and asepsis interference in sweet pepper seeds submitted to incubation for the accelerated aging test (traditional with salt solution). Samples from five different batches of Magali R cultivar sweet pepper were used, submitted or not to asepsis with 1% NaOCl for three minutes, incubated or not to 41oC for 72 hours in saturated NaCl solution or water. The assessment was performed by means of germination and health tests (freezing filter paper). The percentage of Aspergillus spp., Rhizopus sp. and Cladosporium sp. fungi, after incubation for the traditional aging test, was higher than the assessment made before the incubation, that did not occur when salt solution was used. The asepsis, when accomplished before the seed incubation, was efficient in minimizing the incidence of Aspergillus spp. The utilization of NaCl solution in substitution to water in the accelerated aging test inhibited the growth of Aspergillus spp., Rhizopus sp. and Cladosporium sp.