Floral biology and pollen viability of different guava genotypes under the sub-tropics of Jammu and Kashmir

Floral biology plays a crucial role in improving crop management, synchronizing flowering and increasing the efficiency of hybridization. Climatic conditions change with spatial variations, therefore, experiment was carried out in 2024 on different guava cultivars, including Lalit, Hisar Surkha, Hisar Safeda, Punjab Pink, L-49, Shweta, Lalima and Dhawal under sub-tropical conditions of Jammu in Jammu and Kashmir. Among different guava genotypes L-49 exhibited the earliest flowering initiation, starting from 7th August to 20th September 2024 revealing the shortest flowering period of 44 days whereas the longest flowering period was exhibited by Hisar Safeda (57 days). The largest flower diameter was recorded as 45.34 mm in cultivar L-49. However, the smallest flower size was noted in cultivar Lalit with measurements of 30.34 mm. All genotypes featured four green sepals, five to six white petals and an inferior ovary. Cultivar L-49 also had the highest counts for stamens (413.67), stamen length (19.76 mm) and pistil length (15.07 mm). The lowest count of stamens (202.00) and smallest pistil length (9.41 mm) was found in cultivar Dhawal, whereas, lowest stamen length was recorded in cultivar Lalit (11.37 mm). The highest pollen viability tested with 2 percent acetocarmine solution was recorded as 97.33 percent in cultivars L-49 and Lalit, whereas, minimum pollen viability was found in Punjab Pink and Lalima as 94.00 percent. All genotypes displayed a triangular pollen shape. Pollen germination was found to be higher with 10 percent sucrose + 50 ppm boric acid solution as compared to 5 percent sucrose + 50 ppm boric acid and 15 percent sucrose + 50 ppm boric acid solutions. Maximum pollen germination was recorded as 78.66 percent with 10 percent in cultivar Hisar Surkha. In contrast, the lowest pollen grain germination 45.33 percent was recorded in cultivar Dhawal.