A study on seed maturity indices of Ulmus wallichiana Planchon in Kashmir

Abstract

Ulmus wallichiana Planchon (Himalayan elm), a tree species found in the mountainous regions, is known for its multifarious uses. However, overexploitation and problems in its propagation has resulted in it currently reaching the stage of a vulnerable plant species. The present investigation entitled a study on seed maturity indices of Ulmus wallichiana Planchon in Kashmir was carried out to determine the optimal time for collection of Himalayan elm seeds. Samaras/seeds were collected from U. wallichiana trees, beginning in the fourth week of April followed by subsequent collection every 10 days in the year 2021 and 2022, for analysing maturity indices in relation to various physiological characters of seed. The samara colour of U. wallichiana transitioned from cascade green with shining light green wings to pale green colour with light brown centre as maturation progressed, in both years. Moisture content in both years declined from initial to final collection between 88.25 and 86.97% to 10.27 and 8.96 %. Dry matter accumulation steadily increased until the third collection, then rose significantly by the fourth (between 79.91 and 80.14%) and fifth collections (91.73 and 92.04%) in 2021 and 2022. U. wallichiana seeds collected at the final harvest showed maximum germination in both years (81.00% and 81.50% in 2021 and 2022 respectively), when seeds had dried. Thus, the exact knowledge of maturity time of Himalayan elm seeds i.e., 1st week of June in Kashmir valley, will be essential to avoid the collection of immature and non-viable seeds so as to synchronize artificial regeneration of this species, whose regeneration is poor in natural habitats.