Yousef Hakimi; Karim Arab Salmani
Abstract
Genetic variability in a crop population is essential for successful plant breeding. Fifteen cucumber (Cucumis sativus L.) genotypes were evaluated in the greenhouse under the warm condition to estimate the magnitude of their genetic variability and heritability as also morphological and pomological ...
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Genetic variability in a crop population is essential for successful plant breeding. Fifteen cucumber (Cucumis sativus L.) genotypes were evaluated in the greenhouse under the warm condition to estimate the magnitude of their genetic variability and heritability as also morphological and pomological characteristics. Genotypes were also classified in to five groups based on the performance and determination of the highest discriminating characteristic that accounted for more significant variability using cluster analysis and principal component analysis (PCA). The measured characteristics were cucurbit chlorotic yellows virus and fungal severity, off-type plant, stem, internode, leaf, petiole, fruit and fruit trail length, leaf width, male flower percentage, fruit color and groove, fruit diameter, fruit fresh weight, fruit dry matter and ash percentage, fruit pH, EC and TSS, fruit yield, and total fruit number. The IR4 and IR5 genotypes showed the highest fruit yield (460.85 and 425.86 kg/plot) and number (108.72 and 84.22 fruit/plant). IR11 had the highest fruit length of 16.60 cm. High broad-sense heritability was associated with all the traits except for cucurbit chlorotic yellows virus and fungal severity, fruit pH, and total fruit yield. Cluster analysis and its comparison of means showed that IR4 and IR5 from the fifth cluster expressed the best agronomic traits and yield potentials in the warm condition (40°C/32°Cday/night). Hence, selection for any characteristic would favor genotypes in these clusters. The PCA involved fruit dry matter and TSS as the most discriminating trait that accounted for more significant cucumber variability, which should be considered in cucumber improvement programs.
Amin Reza Jamshidi; Ahmad Ghazanfari Moghaddam; Fatameh Mozafari Ghoraba
Abstract
The development of aeroponic cultivation technology has led to more efficient use of water and plant nutrients for producing high quality agricultural commodities. In this research, cucumbers were grown in columnar aeroponic systems for nine weeks and the effect of spraying rate and spraying duration ...
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The development of aeroponic cultivation technology has led to more efficient use of water and plant nutrients for producing high quality agricultural commodities. In this research, cucumbers were grown in columnar aeroponic systems for nine weeks and the effect of spraying rate and spraying duration on the cucumber average yield and water usage efficiency were investigated. The experiments were performed using factorial experiment based on completely randomized designs. The spraying rate had three levels of 125, 250 and 375 mL/min, and the spraying durations were 10, 15 and 20 min. During the experiment, the spraying pumps were turned off for 15 min between each spraying time. Then, the two factors were simultaneously optimized using response surface methodology to maximize fruit yield and water usage efficiency. The ANOVA results showed that both responses were significantly affected by the main effects of the factors (α = 0.01) and by their interaction effects (α = 0.05). The comparison of first and second-order models to show the average yield and water usage efficiency as functions of sparing rate and sparing time indicated that the second-order models fitted with higher accuracies (R2> 80%) to the experimental data than the first-order model. Simultaneous optimization showed that the most suitable spraying rate was 233.37 mL/min and for the spraying duration, it was 16.06 min. At the optimum conditions, the average yield per plant yield was 2.96 kg and the water usage efficiency was 110.37 kg/m3.
