Estimation of single-diode and two-diode solar cell parameters by using chaotic optimization approach (COA) is addressed. The proposed approach is based on the use of experimentally determined current-voltage (I-V) characteristics. It outperforms a large number of other techniques in terms of average error between the measured and the estimated I-V values, as well as of time complexity. Implementation of the proposed approach on the I-V curves measured in laboratory environment for different values of solar irradiation and temperature prove its applicability in terms of accuracy, effectiveness and the ease of implementation for a wide range of practical environment conditions. The COA-based parameter estimation is, therefore, useful for PV power converter designers who require fast and accurate model for PV cell/module.

During two years, germinability and initial growth of seedling of nine foreign varieties and four domestic varieties were studied. The seed is grouped by size (small, medium and large), color (dark transitional and light color of seed coat). Then it was preserved and at three and fifteen months of age in the laboratory and in the field, germinability, dormant seed and growth of shoot and radicle root were examined. In addition to the age, other factors (variety, size, color, period of storage) influenced significantly (P≥0.05 to P≥0.00) on seed germinability and growth of seedling.Higher germinability is achieved from large seeds up to 3.6%. Depending on the seed coat color, the germinability varied to 11%. The seed coat color has had a high impact on maintaining germinability for fifteen months. Seeds with darker coat have also shown higher potential for storage and use in subsequent seeding periods, as determined by the application of the aging test on seed. Significant interdependence (r) was obtained between the germinability test and the growth of seedling in laboratory conditions and in field conditions. Between the germinability and the growth of the shoot and the root, a significant interdependence was established, depending on the varieties (P≥0.05 to P≥0.00).