Growing vegetables
Z. Roudbari; M.R. Imani; J. Sarhadi; S. Khoshkam; R. Yoneszadeh
Abstract
Introduction
To specify the diversity of pepper plant (Capsicum ssp.) population and the inheritance of fruit characteristics for use in seed production breeding programs, there is a need for a diverse population in terms of the characteristics affecting fruit yield. By a large variety of options ...
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Introduction
To specify the diversity of pepper plant (Capsicum ssp.) population and the inheritance of fruit characteristics for use in seed production breeding programs, there is a need for a diverse population in terms of the characteristics affecting fruit yield. By a large variety of options available for each product, there is a greater probability of selecting the best decision. A population's genetic variety may be used in several ways, including selection and hybridization. Pepper is a plant belonging to the genus Capsicum and the family Solanaceae. It is cultivated globally, particularly in tropical and subtropical regions. The genus Capsicum contains more than 30 wild and domestic species, which are classified according to flower structure, fruit, and the number of chromosomes (2n= 24, 26).
Materials and Methods
To compare different pepper species based on fruit morphology, a greenhouse experiment was conducted under hydroponic conditions in Zarandieh region, Markazi province, in a completely randomized design with three repetitions in 2021. The seeds of 42 pepper genotypes from 7 species were obtained from Gene Bank of Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). Initially, the seeds were sown in dedicated planting trays. Once the seedlings had grown six leaves, they were transplanted to the main greenhouse. Within the greenhouse, the rows of cultivation were spaced 160 cm apart, with a 25 cm gap between individual plants. Each genotype was represented by ten plants. Throughout the growing season, the plants were managed by maintaining two branches and removing any surplus ones. In this research, the following characteristics were evaluated: fruit production across three harvests, fruit weight, fruit length and diameter, fruit flesh thickness, fruit flavor (spicy or sweet), unripe fruit color, and ripe fruit color. Descriptive statistics of evaluated trait, including mean, minimum and maximum traits and the percentage of phenotypic and genotypic diversity coefficients, heritability, and the analysis of variance and comparison of means, were used to analyze the data.
Results and Discussion
A diverse collection of pepper was evaluated due to the fruit morphological traits and significant differences among different genotypes in terms of these traits. The average fruit weight of the assessed population was 26.54 g. The minimum and maximum fruit weights of 152.70 and 0.13 g were related to genotypes 409 and 276, respectively. Genotype 318, with an average weight of 144.20 g, was not significantly different from genotype 409. Both genotypes were of the species annuum, but were in two separate groups regarding fruit morphology. The heritability rate of fruit weight was 93%, which is consistent with the results of Usman et al. (2014). Length, diameter and length to diameter ratio (fruit morphology index) are the most important factors in marketing pepper fruit. The mean fruit length, diameter and morphology index were 6.35, 2.57 cm and 3.04, respectively. The highest fruit length was related to genotypes 296 and 318 at 26.33, 20.20 and 19 cm, while the lowest fruit length was 0.70, related to genotype 277. The genotypes with the highest lengths were long pepper and Kapia sweet pepper, respectively, and the genotypes with the shortest lengths tasted spicy. Genotypes 409, 200, 318, 326, 272 and 348 had the largest diameter with 6.50, 6.23, 5.80, 5.67, 5.60 and 5.30 cm, respectively. These genotypes are bell, round, Kapia, triangular, triangular, round and sweet in terms of morphology. The smallest fruit diameter belonged to genotype 293 (0.30 cm), and the nineteen genotypes with a diameter of less than 2 cm did not differ significantly from 293. Twenty genotypes with the smallest fruit diameter have a pungent flavor (Table 1). The range of the fruit morphology index was from 0.56 to 8.99. The lowest and highest values were associated with genotypes 342 and 296, respectively (Table 3). The fruit of genotype 296 was sweet, whereas the fruit of genotype 342 was spicy. The heritability of length, diameter and fruit morphology index were 0.97, 0.97 and 0.98%, respectively. The lowest and highest numbers of fruits per plant in each hand-harvest were 1 and 67 fruits, respectively, belonging to genotypes 342 and 326. However, regarding shallow length, diameter, pulp thickness and, consequently, the low weight of the fruit in genotype 342, an almost low yield of this genotype was obtained in three harvests (2742.67 kg/ha). In contrast, genotype 318, despite its small number of fruits per hand-harvest (3 fruits per hand-harvest), had the highest fruit yield of 25379.20 kg Per hectare due to having fruits with large size and pulp thickness and as a result of high fruit weight. The lowest yields related to genotypes 276 and 293 belonged to C. frutescens L., with fruit yields of 17.60 and 44.00 kg/ha in three harvests. However, there was no statistically significant difference among the performance of these genotypes and the genotypes 277, 210, 282, 358, 261, 332, 394, 304, 311, 407, 321, 215, 427, 203, 342 and 200. The percentage of phenotypic and genetic variations in fruit yield was 61, 55% and the heritability of fruit yield was 81%.
Conclusion
This study evaluated a diverse collection of different species of pepper with a wide range of appearance traits. However, the most desirable and marketable characteristics of the fruit were obtained from genotypes belonging to C. annuum. However, genotypes belonging to other species, which were not addressed due to the high number of fruits per plant and resistance to pests and diseases, can play a complementary role in hybrid seed production breeding programs. Based on the results, genotypes 318 (Kapia, yellow and sweet), 287 (long, red and spicy), 348 (round, red and sweet), 272 (triangular, red and sweet), 309 (black, red and sweet) and 296 (long, red and sweet) could be introduced as cultivars after evaluating their compatibility, in terms of their high yield, suitable size fruits and marketability. In addition, because to the substantial variety of the examined population, breeding efforts might develop hybrid cultivars with unique traits.
Growing vegetables
Z. Roudbari; J. Sarhadi; M. Azadvar; S. M. Alavi-Siney; A. Jalali
Abstract
Introduction
Capsicum is a plant sensitive to temperature fluctuations at day and night, and temperature changes strongly affect the quality of the fruit. Identification of tolerant genotypes to temperature fluctuations that naturally produce parthenocarp and marketable fruit is important for use in ...
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Introduction
Capsicum is a plant sensitive to temperature fluctuations at day and night, and temperature changes strongly affect the quality of the fruit. Identification of tolerant genotypes to temperature fluctuations that naturally produce parthenocarp and marketable fruit is important for use in breeding programs and the production of hybrids with appropriate fruit weight and size and high marketability.
Materials and Methods
In order to evaluate the reaction of the lines related to three populations of sweet pepper (A: red fruit, B: orange fruit and C: yellow fruit) obtained from five generations of self-polination (by generation management by single-seed bulk method), a greenhouse factorial experiment was conducted based on a completely randomized design with three different temperature conditions including optimal day and night temperature (day temperature 25± 2 and night temperature 20 ± 2 °C), low night temperature (day temperature 25± 2 and night temperature 11± 2 °C) and high day temperature (day temperature 40± 2 and night temperature 20 ± 2 °C). For this purpose, 100 lines from each population were planted in three separate greenhouses with the mentioned temperatures. Percentage of seedless fruit lines per population or Parthenocarp fruits (including seedless fruits that had at least 50% by weight of seeded and natural fruits and other seedless fruits that were deformed and small in size (knot) were removed), height Plant, day to ripening and number of fruit lobes per 100 lines of each population were measured in three different temperature conditions. Due to the fact that the lines within each population were different from the other population lines, so the data analysis was performed as a complex sequential-factorial design. Also, due to the importance of fruit characteristics in seedless fruit lines and seeded fruits, analysis of variance of these lines in a completely randomized design (15 treatments in 3 replications) using SAS v software 9.2 was performed and the comparison of the mean of the evaluated traits was performed using Duncan's multiple range test at 5% probability level.
Results and Discussion
The results showed that under optimal temperature conditions, all lines had good growth and no parthenocarpic plants were observed in the evaluated populations, but day and night temperature fluctuations outside the optimal temperature range caused significant changes in plant growth, fruit development. And seeds were formed. The effect of high day temperature on the evaluated characteristics was less than low night temperature. With a sharp drop in night temperature, population A produced the highest percentage of seedless fruit plants. The percentage of parthenocarp lines of populations B and C were significantly lower than population A at low night and daytime temperatures. Population C was less affected by adverse day and night temperatures than the other two populations. Fruit size, fruit weight and fruit shape index, which are the most important determinants of fruit marketing, were strongly affected by day and night temperature fluctuations. In all three populations evaluated, fruit length was significantly negatively affected by low night temperature more than high day temperature, which resulted in distortion of fruit shape index. Fruit shape index, which is the result of the ratio of length to diameter of fruit, in marketable fruits is 1-1.02. As the fruit length increases and the fruit diameter remains constant or decreases, the shape index increases from 1.02, and as the fruit diameter increases with decreasing fruit length, which is usually achieved under cold stress conditions, this number decreases below one. Based on the results, the three populations evaluated had different fruit lengths under optimal temperature conditions, which, with the proportion of fruit diameter to length, the fruit shape index was normal and produced marketable fruits. By decreasing the night temperature below the optimum growth temperature, fruit length decreased sharply in the three evaluated populations, and this decrease was greater in seedless fruits. According to Table 2, the highest percentage of fruit length reduction at low night temperature was observed in population A and in seedless fruits. In this temperature condition, fruit length decreased by 43% in seedless fruits and 17.5% in seeded fruits. The lowest decrease in fruit length at low night temperature was related to population C. Fruit length in seeded and non-seeded fruits of this population decreased by 12 and 24%, respectively. However, the percentage of fruit reduction in the total populations evaluated was 13.90 and 33.69% on average in seeded and seedless fruits, respectively. Although the length of the fruit was less affected by the high temperature during the day than the low temperature at night, but the trend of fruit length changes in these temperature conditions was similar to the low temperature at night. The average decrease in fruit length in the total population in seeded and seedless fruits was 10.41 and 31.52%, respectively, with population C having the least and population A having the most effect from unfavorable daytime temperature. Fruit weight was also affected by the unfavorable temperature of day and night, but the negative effect of low night temperature on fruit weight was more than the unfavorable temperature of the day. According to the results, the percentage of fruit weight loss in seeded and seedless fruits at low temperature at night was 21.19 and 50.06%, respectively, and at high temperature at day, 15.98 and 50.12%. As the results show, seedless fruits had the same effect of unfavorable temperature day and night and showed the highest percentage of weight loss. Also, fruit weight in population C showed the least effect of adverse temperature day and night and no significant difference was observed between populations B and A. Expression is associated with undesirable traits that can be due to the coherence of traits or pleiotropic effects of parthenocarpic genes or physiological or molecular changes. Although in population C the number of lines with Parthenocarp fruit was 1%, but Parthenocarp fruits consisting of size and shape index are more suitable than the other two populations. The C population also showed a low percentage of Knot fruits as well as slight differences in fruit weight and shape at low temperature at night and high temperature at day. Based on the results, the three populations evaluated have different potentials in terms of reacting to adverse low temperatures at night and high temperatures during the day, and this potential can be used in future research and breeding programs to produce hybrids that tolerate temperature fluctuations.
