Scientists at ARI uncover genetic secrets of seedless grapes

Researchers noted that the identification of genes linked to seedlessness could serve as valuable molecular markers, helping breeders develop improved grape varieties with better yield, quality, and adaptability.

In a significant breakthrough for horticulture and crop improvement, scientists from Agharkar Research Institute, in collaboration with Savitribai Phule Pune University, uncovered the genetic and developmental mechanisms behind seedlessness in grapes, a trait highly valued by consumers and the global grape industry.

The seedless trait in this grape mutant is primarily driven by pollen sterility and defects in reproductive development, leading to fruit formation without fertilization, known as parthenocarpy. (REPRESENTATIVE PHOTO)

The study, conducted by a team led by Ravindra Patil and published in the journal, ‘BMC Plant Biology’, on April 1 provides new insights into the molecular and genomic basis of seedlessness, particularly focusing on pollen sterility. The research examined a seedless mutant derived from the high-yielding grape variety ARI-516, developed at ARI.

Through detailed microscopic analysis, researchers found that the seedless mutant exhibited abnormal pollen structure, extremely low viability, and complete failure of pollen germination, indicating that pollen sterility is a major factor behind seedlessness. In addition, the female reproductive structures in the mutant plants were significantly smaller, disrupting fertilization and resulting in seedless berry formation.

The team carried out advanced transcriptomic (RNA sequencing) and whole-genome sequencing analyses at multiple stages of plant development. The findings revealed that several genes responsible for pollen development, cell division, and hormone signalling were significantly downregulated in the seedless mutant. Researchers also identified key genetic mutations, including insertion–deletion variations, that interfere with normal pollen formation.

“The seedless trait in this grape mutant is primarily driven by pollen sterility and defects in reproductive development, leading to fruit formation without fertilization, known as parthenocarpy,” said Patil, explaining the core finding of the study. “The pollen grains are structurally abnormal, exhibit very low viability, and fail to germinate effectively. This impairment disrupts fertilisation, ultimately resulting in the development of seedless fruits.”

Prashant Dhakephalkar, director, ARI, remarked, “The genes identified through this study offer valuable molecular markers that can streamline the development of superior seedless grape varieties. This research lays a solid scientific groundwork for advancing next-generation grape breeding.”

Researchers noted that the identification of genes linked to seedlessness could serve as valuable molecular markers, helping breeders develop improved grape varieties with better yield, quality, and adaptability.