PHYTOSOCIOLOGY AND SOME ECOLOGICAL ATTRIBUTES OF WEED FLORA OF WHEAT IN TEHSIL CHARSADDA KHYBER PAKHTUNKHWA PAKISTAN
Weed infestation of wheat crop is a serious problem throughout the country as well as worldwide, as weeds cause huge yield and quality losses. To investigate the phytosociology of weeds of wheat in Tehsil Charsadda, Khyber Pakhtunkhwa province, Pakistan, a field field survey through Quadrat method was conducted during March and April, 2013. A total of 32 weed species belonging to 18 families were recorded from the research area. The predominant families were Brassicaeae (5 spp.), Poacea and Fabaceae (4 spp. ea.) followed by Polygonaceae, Asteraceae, Caryophlliceae and Plantaginaceae (2 spp. ea.), while the remaining families were represented by only one species each. Five weed communities were established on the basis of importance value constancy index in the investigated area. Coronopus-Poa-Anagallis appears as the predominant community in Tarnab area while at Azeem Khan Pul, Veronica-Coronopus-Melilotus emerged as a dominant weed community. Anagallis-Euphorbia-Veronica, Melilotus-Coronopus-Poa and Polygonum-Ranunculus-Veronica were established as dominant weed communities at Sardheri, Kaptan Kali and Sardaryab area, respectively. Based on the importance value constancy index, Anagallis arvensis (55), Melilotus indicus (54), Euphorbia helioscopia (44), Coronpus didymus (43.5) and Poa annua (37.1) were the dominant weed species in the study area. The Life Form spectra comprised of 84.38% therophytes (18 spp.), 12.5% hemicryptophytes (4 spp.) and 3.13% Chamaephytes (1 sp.). Whereas, the Leaf size spectra showed the predominance of microphylls (53.13%), comprising 17 species, followed by nanophylls (25%) consting 8 species and leptophylls and mesophylls were represented by 18.75% and 3.13%,, consisting 6 and 1 species, respectively. Regarding the Habit of infesting species, it was observed that the annual herbs (75%) comprising 24 species overwhelmed the perennials. Creeping perennial herbs (21.88%) consisted of 7 species, while one species reprepresented creeping perennial shrubs (3.13%). The dominance of annuals could be attributed to the fact that under annual tillage regime the perennials are not successful to establish as their perennating parts are disturbed by tillage, while the short lived annuals germinate, establish, set seed and vanish.