Effect of Pollen Behavior on Seedless Fruit Production of Mutant SoE Mandarin

Abstract

Character improvement of citrus could be done by mutation breeding in which one of the purposes is to obtain seedless fruit. One of the mechanisms of seedlessness is through low viability and germination rate of pollen. This study was aimed to know the behavior of pollen of Mutant SoE Mandarin and its effect on seedless character of the fruit. The research was done in 2015-2016 in Laboratory of ICSFRI. Plant materials used were flowers derived from Mutant plants of SoE Mandarin, which were grown from irradiated budwoods of SoE Mandarin. The irradiated buds were grafted onto 6 months-old rootstocks of Japanese Citroen and maintained in pots in Tlekung Experimental Field ICSFRI. For controls, flowers from local Mandarin (SoE and Batu 55) varieties which were available during the study were used. The pollen were observed on the viability using acetocarmine 1% and successful pollination of flowers. The result showed that there was clearly different pollen viability of the mutant and control plants hence the different seed numbers. Mutant SoE has 36.7% viability and average number of seeds of 2.3 while SoE Mandarin has 98.94% viability and average number of seeds of 11.6. Observation on pollination showed that most pollens were arrested on stigma and less or no pollen found in ovaries of both self-pollinated flowers of Mutant SoE and cross-pollinated flowers of Mutant SoE x Batu 55. This assumed to be the reason of the low number of seeds on mutant fruits.