A field experiment was conducted to quantify the effect of varied water regimes on root length, partitioning of dry matter and plant growth regulators by using sunflower genotypes differing in maturity and drought tolerance. Significant depressing effect of drought stress was evident on traits (i.e., reproductive dry matter, leaf area index and cytokinin concentrations in leaves). However, root/shoot, reproductive/vegetative ratios and Abscisic acid (ABA) concentration were found to increase under drought stress. Drought stress also changed the dry matter accumulation pattern of genotypes. In most cases it reduced the days to reach the maximum peak showing early senescence. ABA was identified as a multi-functional plant growth regulator under drought stress, causing early senescence of plants and translocation of assimilates to the roots and reproductive part while root growth under drought stress was explained by the indole-acetic acid (IAA) concentrations. Maintaining higher cytokinin contents were involved in accumulation of higher reproductive dry matter under drought stress. Although ABA and IAA were both involved in the development of defense responses during the adaptation and survival to drought stress but higher productivity under drought stress was only realized through maintaining higher cytokinin contents.

ABSTRACT. Genetic diversity analysis of chickpea germplasm can provide practical information for the selection of parental material and thus assist in planning breeding strategies. Chickpea seed is a good source of carbohydrates and proteins, constituting 80% of the total dry seed weight. Released cultivars and advanced lines of 30 chickpea genotypes were subjected to RAPD analysis for assessment of genetic diversity. We used 16 RAPD primers. Amplification of genomic DNA of the 30 genotypes yielded 62 fragments that could be scored. The number of amplification products produced per primer varied from two to four, with a mean of three bands. The total number of bands amplified by 16 anchored primers varied from 16 to 34. The primer GLK-15 produced the largest number (N = 4) of fragments, whereas primers GLK-19 and GLD-19 produced the smallest number (N = 1) of fragments. The single 1415 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 9 (3): 1414-1420 (2010 Genetic diversity of chickpea germplasm in Pakistan band produced by the GTGTGCCCCA primer in the PB-2000 and 07005 genotypes may be attributed to temperature tolerance phenotypes.

ABSTRACT. Sorghum ranks fifth in worldwide economic importance among cereal crops and is one of the most important summer annual grasses of Pakistan. As it is a very diverse crop, sorghum genetic fingerprinting requires an efficient marker system. We estimated genetic divergence among 29 sorghum (Sorghum bicolor) genotypes, including approved varieties and local and exotic lines collected from different ecological regions of Pakistan, using random amplified polymorphic DNA (RAPD) markers. A total of 125 RAPD loci, with an average of 66 loci per genotype, were used to calculate genetic divergence among these genotypes, of which 119 were polymorphic, showing 95% overall polymorphism. Genetic similarity ranged from 0.36 to 0.92, indicating a relatively broad genetic base. RAPD analysis revealed maximum similarity between the Indian III and K-A-113 sorghum genotypes (both exotic lines), while the F-601 and F-606 were observed to be the most diverse genotypes. Mean band frequency revealed by these RAPD primers ranged from 0.17 to 0.56, with an average of 0.36. The data presented here support the findings that RAPDs can be effectively used 757 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 9 (2): 756-764 (2010) Biodiversity in the sorghum germplasm of Pakistan for studying genetic diversity in sorghum.

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Drought is the major abiotic stress that limits the crop production at drastic level. Screening of tolerant accessions from available germplasm is the basic step in plant breeding. Sunflower is becoming popular and major oilseed crop in world but unfortunately it is drought sensitive. Screening in field has uncertainties due to the uncontrolled conditions, interaction of biotic and abiotic stresses and variability in environmental factors. Response of the sixty sunflower accessions to drought stress at germination and seedling stage was examined by using polyethylene glycol (PEG-6000) as drought simulator under laboratory. Normal and drought stress treatments i.e. T 1 = zero (control), T 2 =-1.33 MPa and T 3 =-1.62 MPa were developed by dissolving 0, 15 g and 20 g Polyethylene Glycol (PEG-6000) in 100 mL distilled water and a completely randomized design with three replications were used. Promptness, germination, seedling height, fresh weight, dry weight and stress indexes were determined to evaluate the response of sunflower accessions under normal and PEG simulated drought stress treatments. Principal component analysis was used to select the drought tolerant and sensitive accessions. The accessions 017583, A-75, A-79, 017592, G-33, A-48, A-23, G-61, HBRS-1 and 017566 were selected as drought tolerant while, CM-621, 017577, HA-124, HA-133, HA-342 and HA-341 were as drought sensitive. This study may be helpful for the comparison of drought indexes in a controlled experimental assay and for the identification of drought tolerant sunflower cultivars to be used in further breeding programs.