The aim of this study was to estimate the correlation between heterosis in carrot hybrids and the genetic distances of their parents. The experimental material consisted of 15 inbred lines and 34 hybrids. The yield traits (total and marketable yield), as well as quality characters (carotenes, dry matter, total sugar, monosaccharides and nitrates), were evaluated. Heterosis was computed using two measurements of mid-and high-parent heterosis. Genetic distances among lines were calculated using the RAPD and AFLP techniques. Significant heterosis was found for both total and marketable yield. The content of quality compounds for hybrids usually had mid-parent values. Significant correlations were found between molecular distances among lines, measured using RAPD markers, and heterosis of crosses for total yield, and among divergences of parents measured using AFLP markers and heterosis for marketable yield. This appears to contribute towards the carrot hybrid yield prediction by estimation of the genetic distances between parents. This research was undertaken because the possibility of heterosis prediction would allow for the reduction of costs and quicker identification of superior carrot hybrids.
Climate changes lead to a rise in air temperature, which significantly increases the water needs of plants. Maintaining crop productivity will increasingly require the use of plant irrigation. The aim of this study was to assess the water needs of grapevines cultivated in the western provinces of Poland. The calculations were made on the basis of temperature and precipitation measurements collected at three meteorological stations in the period 1981–2010. Water needs were calculated as crop evapotranspiration, which was estimated by crop coefficients and reference evapotranspiration, determined using the Blaney–Criddle formula. The rainfall deficit was assessed by Ostromęcki’s method. The tendency to increase the water needs was observed in each subsequent decade of the thirty-year period, both in the whole growing season (May–October), as well as in June–August and July. The highest values of the linear correlation coefficient for the trend of time variability in water needs occurred from June to August. An analysis of water needs and rainfall deficits indicates the need for the additional irrigation of vineyards in western Poland, especially in very dry years and in June–August. Current research results are helpful in designing vineyard irrigation systems and allow an economical and efficient planning of grapevine irrigation.
The purpose of this research was to determine the water needs and results of drip irrigation of mid-early potato cultivar Courage. Studies were carried out in central Poland in 2011–2013 on very light soil. The experiment was designed as two-factorial trials with four replications. The first factor was drip irrigation: O = control (without irrigation), D = drip irrigation. The second factor was the nitrogen fertilization method: P = broadcasting, F = drip fertigation. Nitrogen fertilization was 120 kg N ha−1 on each plot. Crop coefficients for irrigation period were 0.4 in June and 0.6 in July and August. According to calculations based on the crop coefficients and correction coefficients acc. HargreavesDA model the water requirement of potato for June–August was 202 mm. Drip irrigation increased the marketable tuber yield by 55%. Irrigation water use efficiency increased from 257 kg ha−1 mm−1 in D + P to 264 kg ha−1 mm−1 in D + F. The productivity of 1 kg of nitrogen fertilization was 189 kg ha−1 in control non-irrigated plots and 321 kg ha−1 in drip-irrigated plots, and it rose up to 337 kg ha−1 when fertilization was applied by fertigation.
Four inbred lines of carrot (cytoplasmic male‐steriles and corresponding maintainers) and eight of their F1 hybrids were studied with the amplified fragment length polymorphism (AFLP) technique to examine their genetic relationship and produce markers useful for testing hybrid seed purity. Eighty‐six polymorphic amplicons were identified in bulked DNA samples using eight primer pair combinations. Genetic distance was estimated on the basis of the presence or absence of polymorphic bands. The dendrogram plotted on the basis of the AFLP data closely represented the pedigree relationships of the lines and their hybrids. From one to six amplicons specific for a breeding line were identified. Most of them were also present in the DNA bulks of respective F1 hybrids. However, screening performed on individual plants of two parental lines and the corresponding hybrid indicated insufficient uniformity of parental lines, limiting the applicability of AFLP markers for testing hybrid seed purity.
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