Studies on pollen micro-morphology, pollen storage methods, and cross-compatibility among grape (Vitis spp.)...

Area of Science:

• Plant Science
• Horticulture
• Genetics

Background:

• Successful grapevine improvement relies on understanding pollen morphology, storage, and species compatibility.
• Grape rootstock breeding programs require efficient methods for utilizing diverse genetic resources.

Purpose of the Study:

• To investigate pollen morphology, viability, and storage conditions across ten grape genotypes from three species.
• To assess interspecific compatibility for potential use in grape rootstock improvement.
• To identify optimal pollen storage techniques to overcome asynchronous flowering in grape breeding.

Main Methods:

• Pollen morphology examined using scanning electron microscopy (SEM).
• Pollen viability assessed via 2,3,5-triphenyltetrazolium chloride (TTC) assay.
• In vitro pollen germination tested using a nutrient medium; storage conditions evaluated at room temperature, 4°C, -20°C, and -196°C (liquid nitrogen).

Main Results:

• Variations in pollen micro-morphology observed among genotypes, but not consistently species-wise.
• Acolporated pollen from V. parviflora and Dogridge showed no germination, indicating male sterility.
• Optimal pollen storage achieved at -20°C and -196°C for up to 30 days; room temperature storage limited to 1 day.
• High cross-compatibility noted in V. parviflora × V. vinifera (Pusa Navrang) and V. parviflora × V. champini (Salt Creek) for rootstock breeding.

Conclusions:

• Long-term pollen storage at ultra-low temperatures is feasible, aiding asynchronous pollination in grape breeding.
• Male-sterile genotypes with acolporated pollen can serve as ideal female parents, simplifying emasculation.
• Identified compatible interspecific crosses offer significant potential for developing improved grape rootstocks.