The single nucleotide polymorphisms of the chicken myostatin gene are associated with skeletal muscle and adipose growth

Myostatin, a new member of the TGF-p superfamily, is predominantly expressed in skeletal muscle cells and functions as a negative regulator of skeletal muscle growth in animals. Recently, we have reported three single nucleotide polymorphisms (SNPs) in the chicken my-ostatin gene. Herein, we investigate the association of those SNPs with the production traits in a F2 chicken line derived from Broilers crossing to Silky with the least square analysis. The results show that the BB and AA genotypes are strongly associated with abdominal fat weight (AFW), abdominal fat percentage (AFP), and birth weight (BW) (P < 0.05). Breast muscle percentage (BMP) of the AA type is higher than that of the AB type. The breast muscle weight and breast muscle percentages of F2 individuals have significant difference between CC and DD genotypes (P< 0.05). Breast muscle weight (BMW) of EF birds is higher than that of EE birds (P< 0.05). In this report, we present the first genetic evidence to show that chicken myostatin not o     

Association of polymorphic variants in <Emphasis Type="Italic">MSTN</Emphasis>, <Emphasis Type="Italic">PRL</Emphasis>, and <Emphasis Type="Italic">DRD2</Emphasis> genes with intensity of young animal growth in Pushkin breed chickens

Polymorphic variants in the myostatin, prolactin, and D2 dopamine receptor genes were analyzed in Pushkin breed chickens (n = 231). The rs313744840 single nucleotide polymorphism was studied in the myostatin gene by means of the PCR–RFLP method. The cocks with different genotypes did not differ from each other by the live weight. Chickens with AA genotype were found to be significantly larger than their coevals with AG and GG genotypes at the age of 49 days (P < 0.01). Polymorphism based on the insertion–deletion of a small gene region (indel-polymorphism) was considered in the prolactin and D2 dopamine receptor genes. Differences by the prolactin gene were observed at 7 days of age. The cocks homozygous by the DD deletion were significantly larger than heterozygous ID coevals (P < 0.05). The II cocks significantly differed by the D2 dopamine receptor gene from heterozygous ID coevals by the live weight at 49 and 110 days. In chickens, II homozygotes by the mutation in the D2 dopamine receptor gene were larger than coevals at 7 days, while they had a lower live weight at 110 days (P < 0.05).     

Effect of high-intensity interval training on muscle remodeling in rheumatoid arthritis compared to prediabetes

Background

Sarcopenic obesity, associated with greater risk of cardiovascular disease (CVD) and mortality in rheumatoid arthritis (RA), may be related to dysregulated muscle remodeling. To determine whether exercise training could improve remodeling, we measured changes in inter-relationships of plasma galectin-3, skeletal muscle cytokines, and muscle myostatin in patients with RA and prediabetes before and after a high-intensity interval training (HIIT) program.

Methods

Previously sedentary persons with either RA (n = 12) or prediabetes (n = 9) completed a 10-week supervised HIIT program. At baseline and after training, participants underwent body composition (Bod Pod^®) and cardiopulmonary exercise testing, plasma collection, and vastus lateralis biopsies. Plasma galectin-3, muscle cytokines, muscle interleukin-1 beta (mIL-1β), mIL-6, mIL-8, muscle tumor necrosis factor-alpha (mTNF-α), mIL-10, and muscle myostatin were measured via enzyme-linked immunosorbent assays. An independent cohort of patients with RA (n = 47) and age-, gender-, and body mass index (BMI)-matched non-RA controls (n = 23) were used for additional analyses of galectin-3 inter-relationships.

Results

Exercise training did not reduce mean concentration of galectin-3, muscle cytokines, or muscle myostatin in persons with either RA or prediabetes. However, training-induced alterations varied among individuals and were associated with cardiorespiratory fitness and body composition changes. Improved cardiorespiratory fitness (increased absolute peak maximal oxygen consumption, or VO₂) correlated with reductions in galectin-3 (r = ?0.57, P = 0.05 in RA; r = ?0.48, P = 0.23 in prediabetes). Training-induced improvements in body composition were related to reductions in muscle IL-6 and TNF-α (r < ?0.60 and P <0.05 for all). However, the association between increased lean mass and decreased muscle IL-6 association was stronger in prediabetes compared with RA (Fisher r-to-z P = 0.0004); in prediabetes but not RA, lean mass increases occurred in conjunction with reductions in muscle myostatin (r = ?0.92; P <0.05; Fisher r-to-z P = 0.026). Subjects who received TNF inhibitors (n = 4) or hydroxychloroquine (n = 4) did not improve body composition with exercise training.

Conclusion

Exercise responses in muscle myostatin, cytokines, and body composition were significantly greater in prediabetes than in RA, consistent with impaired muscle remodeling in RA. To maximize physiologic improvements with exercise training in RA, a better understanding is needed of skeletal muscle and physiologic responses to exercise training and their modulation by RA disease–specific features or pharmacologic agents or both.

Trial registration

ClinicalTrials.gov Identifier: NCT02528344. Registered on August 19, 2015.

     

Genome-wide association study on chicken carcass traits using sequence data imputed from SNP array

Chicken carcass traits are economically important for the chicken industry. Detecting which genes affect chicken carcass traits is of great benefit to the genetic improvement of this important agricultural species. To investigate the genetic mechanism of carcass traits in chickens, we carried out a genome-wide association study (GWAS). A total of 435 Chinese indigenous chickens were phenotyped for carcass weight (CW), eviscerated weight with giblets (EWG), and eviscerated weight (EW) after slaughter at 91 days and were genotyped using a 600-K single nucleotide polymorphism (SNP) genotyping array. Twenty-four birds were selected for sequencing, and the 600 K SNP panel data were imputed to sequence data with the 24 birds as the reference. Univariate GWASs were performed with GEMMA software using the whole genome sequence data imputed from SNP chip data. Finally, 3, 25, and 63 suggestively significant SNPs were identified to be associated with carcass weight (CW), eviscerated weight with giblets (EWG), and eviscerated weight (EW), respectively. Six candidate genes, RNF219, SCEL, MYCBP2, ETS1, APLP2, and PRDM10 were detected. SCEL and MYCBP2 were potentially associated with these three traits, RNF219 and APLP2 were potentially associated with EWG and EW, and ETS1 and PRDM10 were only potentially associated with EWG and EW, respectively. Compared with forefathers’ research, 10 reported QTLs associated with CW were located within a 5-Mb distance near the SNPs with P value lower than 1×10^?5. This study enriched the knowledge of the genetic mechanisms of chicken carcass traits.     

The effects of polymorphisms in <Emphasis Type="Italic">growth hormone</Emphasis> and <Emphasis Type="Italic">growth hormone receptor</Emphasis> genes on production and reproduction traits in Aberdeen-Angus cattle (<Emphasis Type="Italic">Bos taurus</Emphasis> L., 1758)

The study was aimed to analyze the relation between individual genotypes and allelic variants of SNPs g.2141C>G of growth hormone gene, g.914T>A and g.257A>G of growth hormone receptor gene with growth and reproduction traits and to evaluate the populationgenetic structure in Aberdeen-Angus cattle (Bos taurus L., 1758) sample of Eastern Ukraine according SNPs studied. Allele C of SNP g.2141C>G has a positive correlation with birth weight, body stature, bigger rump, udder and total exterior evaluation score, shorter calving interval and better calve birth weight and negative correlation with calve average daily gain. Allele T of SNP g.914T>A has positive correlation with the muscle and udder size; live weight in each age, average daily gain, weight and average daily gain of calves born conform to the principle AA>TT≥TA. SNP g.257A>G showed a positive correlation for G allele with muscle size. The population is in equilibrium for SNPs g.2141C>G and g.257A>G, and in disequilibrium for SNP g.914T>A. The analysis showed no linkage disequilibrium between SNPs g.914T>A and g.257A>G. Inbreeding coefficient F_ST in Aberdeen-Angus group studied was 16.1%.     

Polymorphisms of the Myostatin Gene and Its Relationship with Reproduction Traits in the Bian Chicken

Myostatin, or growth and differentiation factor 8, is a member of the transforming growth factor-β superfamily; it functions as a negative regulator of skeletal muscle development and growth in mammals. In this study, single nucleotide polymorphisms in the 5′ regulatory region and exon 1 of the myostatin gene were detected by PCR–SSCP in the Bian, Jinghai, Youxi, and Arbor Acre chickens, and the associations of the polymorphisms with reproduction traits were analyzed. Seven SNPs (A326G, C334G, C1346T, G1375A, A1473G, G1491A, and G2283A) were found in the myostatin gene. Association analysis showed that the G2283A were significantly associated with reproduction traits. Bian chickens of the GG genotype had a greater age at first egg than those of the GA and AA genotypes (P < 0.01). Correspondingly, Bian chickens of the GA and AA genotypes had larger egg number at 300 days than those of the GG genotype (P < 0.05 and P < 0.01, respectively). Bian chickens of the AA genotype had significantly higher body weight at 300 days than those of the GG genotype (P < 0.05). These results suggested that the myostatin gene may have certain effects on reproduction traits other than merely as a negative regulator of skeletal muscle development and growth in mammals previously reported.     

Associations of HSP90AA2 gene polymorphisms with disease susceptibility,glucocorticoids efficacy and health-related quality of life in Chinese systemic lupus erythematosus patients

Although the current glucocorticoids (GCs) treatment for systemic lupus erythematosus (SLE) is effective to a certain extent, the difference in therapeutic effect between patients is still a widespread problem. Some patients can have repeated attacks that greatly diminish their quality of life. This study was conducted to investigate the relationship between HSP90AA2 polymorphisms and disease susceptibility, GCs efficacy and health-related quality of life (HRQoL) in Chinese SLE patients. A case–control study was performed in 470 SLE patients and 470 normal controls. Then, 444 patients in the case group were followed up for 12 weeks to observe efficacy of GCs and improvement of HRQoL. Two single nucleotide polymorphisms (SNPs) of HSP90AA2 were selected for genotyping: rs1826330 and rs6484340. HRQoL was assessed using the SF-36 questionnaire. The minor T allele of rs1826330 and the TT haplotype formed by rs1826330 and rs6484340 showed associations with decreased SLE risk (T allele: P_BH?=?0.022; TT haplotype: P_BH?=?0.033). A significant association between rs6484340 and improvement of HRQoL was revealed in the follow-up study. Five subscales of SF-36 were appeared to be influenced by rs6484340: total score of SF-36 (additive model: P_BH?=?0.026), physical function (additive model: P_BH?=?0.026), role-physical (recessive model: P_BH?=?0.041), mental health (dominant model: P_BH?=?0.047), and physical component summary (additive model: P_BH?=?0.026). No statistical significance was found between HSP90AA2 gene polymorphisms and GCs efficacy. These results revealed a genetic association between HSP90AA2 and SLE. Remarkably, HSP90AA2 has an impact on the improvement of HRQoL in Chinese population with SLE.     

Ammonia elicits a different myogenic response in avian and murine myotubes

Increased myostatin expression, resulting in muscle loss, has been associated with hyperammonemia in mammalian models of cirrhosis. However, there is evidence that hyperammonemia in avian embryos results in a reduction of myostatin expression, suggesting a proliferative myogenic environment. The present in vitro study examines species differences in myotube and liver cell response to ammonia using avian and murine-derived cells. Primary myoblasts and liver cells were isolated from embryonic day 15 and 17 chick embryos to be compared with mouse myoblasts (C2C12) and liver (AML12) cells. Cells were exposed to varying concentrations of ammonium acetate (AA; 2.5, 5, or 10 mM) to determine the effects of ammonia on the cells. Relative expression of myostatin mRNA, determined by quantitative real-time PCR, was significantly increased in AA (10 mM) treated C2C12 myotubes compared to both ages of chick embryonic myotube cultures after 48 h (P < 0.02). Western blot analysis of myostatin protein confirmed an increase in myostatin expression in AA-treated C2C12 myotubes compared to the sodium acetate (SA) controls, while myostatin expression was decreased in the chick embryonic myotube cultures when treated with AA. Myotube diameter was significantly decreased in AA-treated C2C12 myotubes compared to controls, while avian myotube diameter increased with AA treatment (P < 0.001). There were no significant differences between avian and murine liver cell viability, assessed using 2′, 7′- bis-(2-carboxyethyl)-5-(and-6-)-carboxyfluorescein, acetoxymethyl ester, when treated with AA. However, after 24 h, AA-treated avian myotubes showed a significant increase in cell viability compared to the C2C12 myotubes (P < 0.05). Overall, it appears that there is a positive myogenic response to hyperammonemia in avian myotubes compared to murine myotubes, which supports a proliferative myogenic environment.     

Association of the apolipoprotein M gene polymorphisms and serum lipid levels

The association of rs707921 and rs707922 SNPs in the apolipoprotein M (APOM) gene and serum lipid levels is still controversial. This study aimed to detect the association of the APOM rs707921 and rs707922 SNPs and several environmental factors with serum lipid profiles. Genotyping of rs707921 and rs707922 was performed in 703 of Mulao’s and 707 of Han’s participants. The serum levels of TG in Mulao, and TG and HDL-C in Han were different between the A and C allele carriers of rs707921 (P < 0.05–0.01); while the serum levels of TG in both Mulao and Han were different between the T and G allele carriers of rs707922 (P < 0.05–0.01). According to the gender-subgroup analysis, the levels of TC in Mulao females, TG and ApoB in Han males, and HDL-C in Han females were associated with the genotypes of rs707921 (P < 0.05 for each); whereas the levels of TG in Mulao males, and TG and ApoB in Han males were correlated with the genotypes of rs707922 (P < 0.05 for each). Serum lipid parameters were also associated with several environmental factors (P < 0.05–0.001). The APOM gene rs707921 and rs707922 SNPs are associated with some serum lipid parameters in the two ethnic groups, but the trends of association suggest that the two SNPs might have racial/ethnic- and/or gender- specificity.     

Genome-wide association study of body weight in Wenshang Barred chicken based on the SLAF-seq technology

Chicken body weight (BW) is an economically important trait, and many studies have been conducted on genetic selection for BW. However, previous studies have detected functional chromosome mutations or regions using gene chips. The present study used the specific-locus amplified fragment sequencing (SLAF-seq) technology to perform a genome-wide association study (GWAS) on purebred Wengshang Barred chicken. A total of 1,286,715 single-nucleotide polymorphisms (SNPs) were detected, and 175,211 SNPs were selected as candidate SNPs for genome-wide association analysis using TASSEL general linear models. Six SNP markers reached genome-wide significance. Of these, rs732048524, rs735522839, rs738991545, and rs15837818 were significantly associated with body weight at 28 days (BW28), while rs314086457 and rs315694878 were significantly associated with BW120. These SNPs are close to seven genes (PRSS23, ME3, FAM181B, NABP1, SDPR, TSSK6L2, and RBBP8). Moreover, 24 BW-associated SNPs reached “suggestive” genome-wide significance. Of these, 6, 13, 1, and 4 SNPs were associated with BW28, BW56, BW80, and BW120, respectively. These results would enrich the studies on BW and promote the use of Chinese chicken, especially the Wenshang Barred chicken.     

Plasma matrix metalloproteinase-9 levels, <Emphasis Type="Italic">MMP</Emphasis>-<Emphasis Type="Italic">9</Emphasis> gene haplotypes,and cardiovascular risk in obese subjects

Plasma matrix metalloproteinase (MMP)-9 is a predictor of cardiovascular mortality, and MMP-9 polymorphisms affect plasma MMP-9 levels. However, no study examined whether MMP-9 haplotypes affect MMP-9 levels in obese adults. We examined whether MMP-9 polymorphisms and haplotypes are associated with obesity, and whether they affect MMP-9 levels in obese subjects. We examined the plasma levels of MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 in 105 subjects with normal weight (controls), 100 obese subjects, and 156 obese subjects with ≥3 metabolic risk factors (MRFs). We determined genotypes for three polymorphisms: C-1562T (rs3918242), Q279R (A>G, rs17576), and R668Q (G>A, rs17577). MMP-9 levels and activity (MMP-9/TIMP-1 ratio) were higher in obese subjects than in controls (P < 0.05). However, MMP-9 levels were higher in obese subjects with ≥3 MRFs than in obese subjects (P < 0.05). Obese subjects with ≥3 MRFs carrying the GA+AA genotypes for R668Q (G>A) polymorphism had higher MMP-9 levels than subjects carrying the AA genotype (P < 0.05). The “T, G, A” haplotype was more common in both groups of obese subjects than in controls (OR 3.95 and 4.39, respectively; P < 0.01). Notably, obese subjects with ≥3 MRFs carrying the “T, G, A” haplotype had higher MMP-9 levels than subjects carrying the “C, A, G” reference haplotype (P < 0.05). The “T, G, A” haplotype was associated with an increased risk of obesity and affected MMP-9 levels in obese subjects with ≥3 MRFs. Our findings suggest that plasma MMP-9 levels and MMP-9 haplotypes may help to discriminate obese subjects at an increased cardiovascular risk.     

Novel SNPs of the bovine <Emphasis Type="Italic">NUCB2</Emphasis> gene and their association with growth traits in three native Chinese cattle breeds

In this study, polymorphism in the exon 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11 of bovine NUCB2 gene was detected by PCR-SSCP and DNA sequencing methods in 686 individuals from three Chinese cattle breeds. Two haplotypes (M and N), three observed genotypes (MM, MN and NN) and two SNPs (NC_007313: g. 27451G>A, NC_007313: g. 27472T>C) were detected. The frequencies of haplotypes M and N in inland Chinese three breeds were 0.531–0.721 and 0.279–0.469 respectively. The studied showed that Nanyang, Jiaxian Red and Qinchuan cattle populations were in Hardy–Weinberg equilibrium at SNPs locus of NUCB2 gene (P > 0.05). Polymorphism of the NUCB2 gene was shown to be associated with growth traits in Qingchuan and Nanyang cattle breed. The linkage of two mutant sites in the bovine NUCB2 gene had significant effects on body length, body weight, heart girth, and average daily gain at 24 months (P < 0.05). Results of this study suggested that the NUCB2-gene-specific SNP may be a useful marker for growth traits in future marker-assisted selection programmes in inland Chinese cattle.     

Genotypical features in the expression of allozymes of β-specific hydrolase of carboxylic esters in wild-type <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The expression level of electrophoretically separated S- and F-allozymes of β-specific esterase (EC 3.1.1.2) in genotypes of wild-type Drosophila melanogaster (males and females) that are monozygous or heterozygous with respect to the locus β-Est is determined by means of computerized densitometry; α-naphthylacetate, β-naphthylacetate, and α-naphthylpropionate are used as the substrates. The intensity of the expression of the esterase is judged from the quantity of reaction product created as a result of simultaneous azo coupling between naphthol and diazonium in 4, 24, 44, and 64 min incubation times. Reliable differences in the expressions of the S- and F-allozymes as a function of the structure of the β-Est locus of genotypically distinct individuals are established. In all the variant experiments, a higher level of summary activity of the S- and F-allozymes of the β-esterase of the heterozygotes by comparison with the individual activity of the F-and S-allozymes of the corresponding homozygotes was demonstrated, independently of the sex of the Drosophila individual. A comparative estimate of the temporal dynamics of the expression of in vitro allozymes of the dominant homozygotes (β-Est _S /β-Est _S ), heterozygotes (β-Est _S /β-Est _F ), and recessive homozygotes (β-Est _F /β-Est _F ) is performed. Possible mechanisms for the occurrence of heterosis according to the character of expression of S- and F-allozymes of β-esterase on the basis of the theory of biochemical enrichment of heterozygote genotypes are considered.     

Single nucleotide polymorphism markers linked to root elongation rate in sugar beet

The aim of this study was to identify single nucleotide polymorphism (SNP) markers genetically linked to root elongation rate (RER) in sugar beet (Beta vulgaris L.). A population of 244 F₃ individuals, obtained from the cross between lines L01 (a low RER) and L18 (a high RER), was phenotyped by measuring RER of 11-d-old seedlings grown in a hydroponic culture. Two DNA bulks of 50 F₃ individuals with extreme phenotypes were used for bulk segregant analysis by restriction-associated DNA sequencing. A total of 20 376 SNPs were identified. Single nucleotide polymorphisms were filtered to reduce the number of the false positive and mapped on candidate chromosomal regions of the B. vulgaris reference genome. One of the total of SNPs selected, SNP10139, was strongly linked to RER (P < 0.01). The pattern of association between the SNP10139 genotype and RER was also evaluated on a breeding line panel comprising 40 low and 40 high RER individuals with different allele frequencies between groups (P < 0.01). The SNP10139 sequence was mapped on the B. vulgaris peptide transporter (PTR) gene, a carrier that influences root elongation in Arabidopsis thaliana. Our results suggest that SNP10139 influence RER in sugar beet, and sequence information can be used in marker-assisted selection programs.     

Association of kidney structure-related gene variants with type 2 diabetes-attributed end-stage kidney disease in African Americans

African Americans (AAs) are at higher risk for developing end-stage kidney disease (ESKD) compared to European Americans. Genome-wide association studies have identified variants associated with diabetic and non-diabetic kidney diseases. Nephropathy loci, including SLC7A9, UMOD, and SHROOM3, have been implicated in the maintenance of normal glomerular and renal tubular structure and function. Herein, 47 genes important in podocyte, glomerular basement membrane, mesangial cell, mesangial matrix, renal tubular cell, and renal interstitium structure were examined for association with type 2 diabetes (T2D)-attributed ESKD in AAs. Single-variant association analysis was performed in the discovery stage, including 2041 T2D-ESKD cases and 1140 controls (non-diabetic, non-nephropathy). Discrimination analyses in 667 T2D cases-lacking nephropathy excluded T2D-associated SNPs. Nominal associations were tested in an additional 483 T2D-ESKD cases and 554 controls in the replication stage. Meta-analysis of 4218 discovery and replication samples revealed three significant associations with T2D-ESKD at CD2AP and MMP2 (P _corr < 0.05 corrected for effective number of SNPs in each locus). Removal of APOL1 renal-risk genotype carriers revealed additional association at five loci, TTC21B, COL4A3, NPHP3-ACAD11, CLDN8, and ARHGAP24 (P _corr < 0.05). Genetic variants at COL4A3, CLDN8, and ARHGAP24 were potentially pathogenic. Gene-based associations revealed suggestive significant aggregate effects of coding variants at four genes. Our findings suggest that genetic variation in kidney structure-related genes may contribute to T2D-attributed ESKD in the AA population.     

Identification of a nuclear-recessive gene locus for male sterility on A2 chromosome using the Brassica 60 K SNP array in non-heading Chinese cabbage

WS24-3 is a newly bred recessive genic male sterility line of the non-heading Chinese cabbage (Brassica rapa ssp. chinensis). Here, an F₂ population was produced from the cross between WS24-3 and a male-fertile breeding line (WS135). The Illumina Brassica 60 K single nucleotide polymorphism (SNP) array was used for SNPs detecting between sterile and fertile bulks from the F₂ population, and 62 SNPs were identified. BLAST analysis of the 62 SNPs revealed that the A2 chromosome of Brassica rapa genome contained 22 SNPs, whereas the other chromosomes did not contain more than 6 SNPs each. These data indicated that the potential target gene locus, named Bra2Ms, might be located on A2. Based on 10 of the 22 SNPs, allele-specific-polymerase chain reaction (AS-PCR) primers and single sequence repeat (SSR) primers were designed, 5 AS-PCR primers and 9 SSR primers showed difference between the bulks in electrophoretic determination. Analysis of these markers in F₂ population revealed that Bra2Ms was genetically delimited to a region of 1.2 cM. We also detected two co-segregated markers SSRa2-951 and SSRa2-960 in this region. The markers identified in our study might facilitate the transfer of recessive genic male sterility alleles to other favorable genetic backgrounds. Furthermore, these markers will support a map-based clone of Bra2Ms.     

Polymorphisms of the myostatin gene and its relationship with reproduction traits in the bian chicken

Myostatin, or growth and differentiation factor 8, is a member of the transforming growth factor-β superfamily; it functions as a negative regulator of skeletal muscle development and growth in mammals. In this study, single nucleotide polymorphisms in the 5' regulatory region and exon 1 of the myostatin gene were detected by PCR-SSCP in the Bian, Jinghai, Youxi, and Arbor Acre chickens, and the associations of the polymorphisms with reproduction traits were analyzed. Seven SNPs (A326G, C334G, C1346T, G1375A, A1473G, G1491A, and G2283A) were found in the myostatin gene. Association analysis showed that the G2283A were significantly associated with reproduction traits. Bian chickens of the GG genotype had a greater age at first egg than those of the GA and AA genotypes (P?相似文献   

Evaluation of wild <Emphasis Type="Italic">Arachis</Emphasis> species for cultivation under semiarid tropics as a fodder crop

Wild Arachis genotypes were analysed for chlorophyll a fluorescence, carbon isotope discrimination (ΔC), specific leaf area (SLA), and SPAD readings. Associations between different traits, i.e., SLA and SPAD readings (r =–0.76), SLA and ΔC (r = 0.42), and ΔC and SPAD readings (r = 0.30) were established. The ratio of maximal quantum yield of PSII photochemistry (F_v/F_m) showed a wider variability under water deficit (WD) than that after irrigation (IR). Genotypes were grouped according to the F_v/F_m ratio as: efficient, values between 0.80 and 0.85; moderately efficient, the values from 0.79 to 0.75; inefficient, the values < 0.74. Selected Selected genotypes were evaluated also for their green fodder yield: the efficient genotypes ranged between 3.0 and 3.8, the moderately efficient were 2.6 and 2.7, the inefficient genotypes were of 2.3 and 2.5 t ha^?1 per year in 2008 and 2009, respectively. Leaf water-relation traits studied in WD and IR showed that the efficient genotypes were superior in maintenance of leaf water-relation traits, especially, under WD. Potential genotypes identified in this study may enhance biomass productivity in the semiarid tropic regions.