Identification of poplar (Populus deltoides Bartr.) clones through leaf protein profiling

Abstract

Poplar (Populus deltoides Bartr.) is one of the most important agroforestry tree species. Many genetically improved poplar clones have been developed for northwestern regions of India. Clonal identification before planting the poplars is helpful in maintaining the purity of clones and achieving higher yield thus saving labour, energy and time. Morphological identification of poplar clones is quite difficult due to lack of distinctive phenotypic features. Gel electrophoresis technique is being increasingly used as an additional tool in research programmes dealing with identification of cultivars, genomes for tracing back the evolution of various groups of plants [1, 2]. The present investigation was carried out to identify prominent clones through study of their leaf protein profiles. Nine poplar clones viz., G3, G48, 0121, 0163, S7C1, S7C4, S7CS, S7C15 and S7C20 were used. Most of the clones were introduction in India from Europe and the United States of America and few clones were developed in India using introduced material. For preparing protein extract, 5 g of young leaves were homogenized with 400 f..ll of chilled extraction buffer (to prepare extraction buffer 0.124 g boric acid and 0.762 g borax were dissolved separately in 100 ml distilled water, then 25 ml solution of boric acid was taken and added slowly solution of borax to it, upto pH reaches to 8.9 then added 10 g sodium chloride and make volume upto 100 ml). The samples were left in refrigerator for 1 hour. The contents were centrifuged at 2000 g for 20 minutes and to the supernatant an equal amount of sample buffer was added. The samples were electrophoresed in 12 per cent SOS-poly acrylamide gel using 20 mA current for 30 minutes followed by 30 mA current. Later gel was viewed and photographed.