Phenological and genetical Study of perennial grasses in Khorassan
2004
Gazanchian, Ali | Zarif Ketabi, Hamed | Paryab, Asghar
The grass family (Poaceae) is dispersed throughout the world. Its estimated that one-sixth of genera of this family grow in Iran. The perennial grasses are important due to soil conservation, forage production and livestock grazing. These grasses are also well adapted to arid and semi-arid regions. Thus, the first study must be focused on understanding of genetic diversity. However, the study of plant phenology has essential role for grass surviving and range management especially in dry conditions. The most important phonological stages of grasses are a) vegetative (from germination to tillering) b) transition (from shoot elongation booting stage), and c) reproductive or flowering (from booting stage to seed setting). There are an estimated of 129 grass species (54 annual and 75 perennial) in Khorassan. This project was conducted to evaluate grass dispersion and phenology, at Sisab station, from 1994-2002. Seeds were collected from different sites of Khorassan and planted in pot, then transplanted to field on early April in each year. Result showed that grasses growth was delayed in all of species at first year. Phenology was completely studied after establishment at second year. Grasses could be divided in three groups including a) Early growth in spring such as populations of Festuca ovina and Bromus tomentellus that went to jointed stem in late March and began flowering in early May, then seed matured in mid-June and immediately began to shedding by late June. b) late growth in spring such as Agropyron spp, Elymus baldchuanicus, and Leocopoa sclerophylla that showed jointed stem from late April to mid-May and head appearance in early June, then seed maturation in late June and seed shedding by late in summer. This group was severely affected by soil moisture and temperature particularly in filling stage. c) Intermediate group, including Festuca arundinaceae, Dactylis glomerata, Stipa spp, Melica spp, Hordeum bulbosum. The jointed stem stage is very important for regrowth and grazing management in perennial grasses. Species showed a variety of 50 days at this stage in north of Khorassan conditions. We concluded that all species except Festuca arundinaceae and Bromus kupetdaghensis were well adapted to new conditions. A better understanding of plant phenology in perennial grasses could help to improve rangeland managing programs in order to get to maximum productivity in arid and semi-arid areas. According to existing genetic diversity of grasses we can suggest the best combination of species for renovation of rangelands in future studies.
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