การคัดเลือกแบบหมู่ประยุกต์และการสกัดสายพันธุ์ฟักทองประดับ

Abstract

Ornamental pumpkins have historically been used in some ceremonial practices according to the particular religious faith. Presently, ethnic Chinese and Chinese descendants still incorporate these pumpkins as an offering to worship deities in their Chinese New Year and Ghost Festival ceremonies. Symbolically, the white ornamental pumpkin represents "silver", while the orange variant corresponds to "gold". Mature pumpkins exhibit robust rinds and peduncles. Enhancing crop productivity and improving the frequency of white and orange skin fruits in ornamental pumpkin populations are fundamental strategies to both increase outputs per unit area and achieve high-quality yields. The experiment comprised two sub-experiments. The first involved variety selection through modified mass selection and inbred line selection of ornamental pumpkins. The objective was to assess the selected populations or varieties. The evaluation was conducted on the responses to three cycles of modified mass selection for prolificacy and the frequency of white and orange fruits in ornamental pumpkin populations. These populations were assessed using a randomized complete block design (RCBD) with four replications at Agricultural Innovation, Demonstration, and Training Center, Faculty of Agriculture, Chiang Mai University, from November 2020 to January 2021. The results revealed an increase in the number of fruits per plant in the three selected cycles (M3) for both colors’ populations compared to the original population (M0). The white population showed an increase of 1.7 fruits per plant per cycle, with a percentage increase of 88.6%, while the orange population demonstrated a similar increase of 1.7 fruits per plant per cycle, with a percentage increase of 97.9%. Regarding fruit color skin traits, the white fruit skin frequency of M3 white populations increased by 33.3% from the original population, whereas the orange fruit skin frequency of M3 orange populations increased by 27.0% from the original population. These findings suggest that modified mass selection can effectively enhance the number of fruits per plant and fruit skin frequency in ornamental pumpkin populations. This improved population serves as a valuable genetic resource for the development of inbred lines. The assessment was made on the growth characteristics, fruit yield, and quality of white and orange inbred pumpkin varieties selected through five cycles of inbreeding, alongside parent and commercial varieties. These evaluations were conducted across two seasons: winter (December 2020 to February 2021) and rainy (June and August 2021), utilizing a randomized complete block design (RCBD) with three replications at Agricultural Innovation, Demonstration, and Training Center, Faculty of Agriculture, Chiang Mai University. In the white group, significant differences were observed among varieties for all studied characteristics. While variations were noted among environments and variety-environment interactions regarding the number of fruits per plant, no distinctions were found in fruit size. Notably, selected varieties exhibited a higher fruit count compared to commercial ones, albeit with smaller fruit sizes. Across both winter and rainy seasons, the number of fruits per plant remained consistent (2.8 and 2.5 fruits, respectively); yet winter fruits were heavier and larger in diameter compared to rainy season fruits (241.3 grams and 8.6 centimeters versus 205.5 grams and 7.9 centimeters). Thus, white ornamental pumpkin production across the two seasons did not affect fruit count but did influence fruit size, with winter fruits being larger and displaying a white skin color for selected varieties. In the orange group, significant differences were observed among varieties for both the number of fruits per plant and fruit size. Similarly, variations were found among environments for the number of fruits per plant, and variety-environment interactions were noted for fruit diameter and length. Selected varieties exhibited a higher fruit count per plant compared to commercial varieties, albeit with smaller fruit sizes. During the rainy season, the number of fruits per plant surpassed that of the winter season (3.6 versus 2.6 fruits, respectively), with no discernible impact on fruit size. Consequently, orange ornamental pumpkin production during rainy seasons resulted in a higher fruit count per plant compared to winter production. The fruit skin color of selected varieties remained consistently orange across both seasons. Experiment 2 aimed to study the expression characteristics of genes controlling white and orange fruit skin colors through reciprocal crosses between white and orange ornamental pumpkin varieties selected from 6th generation breeding lines. These crosses were evaluated for fruit skin color segregation during the rainy season (June to August 2021), employing a randomized complete block design (RCBD) with three replications at Agricultural Innovation, Demonstration, and Training Center, Faculty of Agriculture, Chiang Mai University. The results showed that the L*, chroma, and hue angle of the first crossing (W26-3-1-8-5-10-1 x O18-6-3-5-2-8-1) and the second crossing (O18-6-3-5-2-8-1 x W26-3-1-8-5-10-1) were not significantly different from the parent variety W26-3-1-8-5-10-1, which has white fruit skin color. Specifically, the first crossing, second crossing, and parent variety W26-3-1-8-5-10-1 had L* values of 89.3, 88.9, and 90.1, respectively; chroma values of 14.3, 15.5, and 14.6, respectively, and hue angles of 91.2º, 91.2º, and 90.4º, respectively. Furthermore, the L*, chroma, and hue angle of the first and second crossings, as well as the parent variety W26-3-1-8-5-10-1, were significantly different from the parent variety O18-6-3-5-2-8-1, which has orange fruit skin color. This indicates that the white fruit color trait is controlled by a dominant gene, while the orange color trait is controlled by a recessive gene.