Environment Conservation Journal (Feb 2024)

Optimization of in vitro pollen storage conditions in seeded and low-seeded citrus genotypes

  • Kunzang Lamo,
  • Anil Kumar Sangwan ,
  • Navprem Singh,
  • Manveen Kaur Batth

DOI
https://doi.org/10.36953/ECJ.25182699
Journal volume & issue
Vol. 25, no. 2

Abstract

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An in vitro pollen storage study was conducted using pollen from three seeded citrus plant genotypes, viz., ‘Mexican lime’, ‘W’. Murcott’ and ‘Mosambi’ and five seedlesscitrus genotypes, viz., ‘Lisbon lemon’, ‘Jaffa’, ‘Clementine’, ‘Hamlin’ and ‘Mukaku Kishu’. Pollen viability and germination percentage were evaluated at different storage temperature treatments, i.e., at room temperature (in anhydrous calcium chloride) (control), in a refrigerator at 4°C, in a freezer (-20°C), and in a freeze drier (-80°C). The viability of the pollen plants was tested with an acetocarmine stain (2%). Among all the tested sucrose concentrations (0, 5, 10, 15, 20, and 25%) for in vitro pollen germination, the 15% sucrose concentration had the highest effect on pollen germination. The results showed significant differences in pollen viability and germination under different storage temperature conditions. The pooled data revealed that, among the seeded genotypes, W. Murcotts showed the maximum mean viability and germination percentage (67.86% and 60.88%, respectively) after 48 weeks of storage at -80°C, and the minimum values were observed for Mexican lime (46.57% and 33.71%, respectively). However, in the low-seeded genotype, Mukaku Kishu had the maximum mean pollen viability and germination (71.52% and 64.07%, respectively) after 48 weeks of storage at -80°C, and the lowest values were observed in Jaffa (39.36% and 28.08%, respectively). The results indicate that the freeze drier storage temperature (-80°C) had the greatest effect on retaining pollen viability and germination in both the seeded and low-seeded genotypes. However, a progressive decrease in pollen viability and germination rate was observed with increasing duration at all storage temperatures, reaching a minimum at 48 weeks after storage. However, the reduction in pollen storage ability was greatest at room temperature and 40°C. Pollen grains stored at low temperatures (-80°C and -20°C) showed good viability and germination percentage compared with those stored at room temperature and 4°C.

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