Studies on Pollen Viability, Preservation and Pollination in Seed Production of Hot Pepper (Capsicum annuum L.)

• Main Authors: Horng-Yeuan Kuo, 郭宏遠
• Other Authors: 宋妤
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/56750217884111489804

博士 === 國立中興大學 === 園藝學系所 === 101 === Hot pepper (Capsicum annuum L.) is the important spicy vegetable in the world. For commercial F1 cultivars, the variety purity and seed quality is considered to be very important. Due to the climate warming and plant variety protection, the demand of heat-tolerant lines, protection of the parental lines of hybrid variety, cut-down the cost of seed production grow up increasingly. The purpose of this study were to select the heat-tolerance lines, test the pollen quality, and storage pollen in liquid nitrogen, providing for assessing the feasibility of honeybees to carry pollen for pollination. The results showed that in vitro method (pollen incubated on B&K solid medium with 10 % sugar) and histochemical method ( 0.5 % TTC solution) were both rapid test methods for pollen vigor. Line hp27, having better heat-tolerance, was selected from four entry lines by pollen performances through the growth period. There was a positive correlation between pollen germination percentage and flower bud length, which could be used as a rapid test method for pollen vigor in the field. It was helpful for enhancing pollen vigor, seed number and quality by soil irrigated Hoagland Solution(-B) plus 2.5ppm B once a week after transplanting into the pot for two weeks. The relative water content in anther would affect pollen vigor. The effects of the different dehydration treatments on anther relative water content and pollen viability of hot pepper was studied. The results of the flower bud predehydration for one and two days showed that the pollen germination percentage dried by calcium chloride and desiccators (15℃/ 8 % RH) were 81.2 % and 81.0 %, respectively. The decrease of pollen moisture content and starch as well as the increase of sucrose were occurred during flower bud dehydration process. In order to understand the suitable temperature for pollen preservation of hot peper, different temperatures and liquid nitrogen were used as storage conditions to apply on germplasm preservation, breeding and seed production of hot pepper were researched in this study. The results showed that pollen could only maintain vigor for three days in room temperature. The vigor of pollen storaged in 4 ℃ consistently declined until ninth week that no germination was obtained. In addition, the seeds per fruit and seed germination percentage of both -20 ℃ and cryopreservation treatments were still the same with fresh pollen treatment. Furthermore, 40 ℃ water bath for 3-5 min was suitable for thawing after pollen cryopreservation. The pollen cryopreserved for one year could maintain its vigor, structure and genetic stability. New protein (fructokinase-2) in pollen was induced by super chilling and higher ATP content was detected in the germinating pollen. The cytoplasmic male sterile lines of hot pepper were grown in the net-house for assessing the feasibility of honeybee pollination in seed production of hot pepper in the study. We found that CMS line C was suitable for honey bee pollination in seed production due to its larger flowers, more nectar secretion, and higher honey bee foraging frequency compared to other lines tested. When relying on honey bees to do pollination in the closed net-house, the male and female parents (♂:hp27,♀:C) grown in 1:1 ratio within the same row could obtain more seed production. Both fresh and liquid nitrogen preserved pollen could be used for honeybees to carry them for pollination and make successful fruit-sets and seed production. However, using bee pollination yielded less seeds than using hand-pollination. After generalized assessment of study results described above, line hp27 had a better heat-tolerance, whose pollen vigor was enhanced by the following fertilizer treatment: Hoagland Solution(-B) plus 2.5ppm B by soil irrigation once a week after transplanting into the pot for two weeks. Pollen should be preserved in the liquid nitrogen when the relative moisture content of the anther was dried to 45-50% after flower bud pre-dehydrated for two days. Both labor-saving and carrying-pollen pollination by honeybee with cytoplasmic male line C grown in the net-house were successful for fruit-sets and seed production, but using bee pollination this way yielded less seeds than using hand-pollination about 43.5 %.