Field Evaluation of Some Recently Developed Selections for High Nodulation And Value of Nodulation Variants of Chickpea

Naturally occurring plants with large differences in nodulation capacities (including nonnodulation) within chickpea cultivars have been reported. Two cultivars, ICC 4948 (= G 130) and ICC 5003 (= K 850), from which such nodulation variants were identified during the mid-1980s, were susceptible to fusarium wilt a widely occurring soilborne disease, caused by Fusarium oxysporum f. sp. ciceri. This made multilocational evaluation of the nodulation variants difficult in some important chickpea- growing areas. Studies reported here suggest that high-nodulating variants can be identified from advanced breeding chickpea lines that were reported as tolerant to fusarium wilt. The potential value of these and previously reported nodulation variants for quantification of N2 fixation, additional residual effect owing to additional N2-fixation by the high nodulating selections, improving soil health, and better understanding of the symbiotic process have been discussed. The potential to develop stress- tolerant symbiotic chickpea lines has been indicated through successful identification of high mineral-N tolerant symbiotic selections

Natural occurrence and salient characters of nonnodulating chickpea plants

Nonnodulating (Nod−1) lines are a valuable reference for assessing the amount of biologically fixed N2 in a legume. Chance observation of a Nod~ plant in chickpea (Cicer arietinum L.) accession ICC 435 encouraged us to study the frequency of natural occurrence of this trait. Six hundred forty to 36260 plants of each of 11 chickpea accessions, field-grown under conditions favoring good nodulation, were uprooted for nodulation observations at 22 and 112 days after sowing (DAS). Plants identified as Nod- at 22 DAS were potted to produce seeds and those at 112 DAS had physiologically mature seeds. Progenies of apparent Nod- plants were inoculated with chickpea Rhizobium strain 1C 59 and grown in pots for 28 d for confirmation. The frequency of Nod- plants in four accessions (ICC 435, −4918, −5003 and −4993) ranged from 120 to 490 per million. One Nod- plant from each of the four accessions was used for reconfirmation studies in the postrainy season 1987-1988 and for agronomic evaluation in subsequent studies under field conditions. The Nod- selections were indistinguishable from their respective parent accessions for plant growth except for nodulation, and most yielded similarly to their Nod* accessions when supplied with 50 to 100 kg N ha−1. On a low-N field without fertilizer N, the Nod− plants were light green, grew poorly, had a short internodal distance with small leaves and leaflets, and had reddish-brown pigment on margins of leaflets, rachis, and sometimes branches

Identification of non-nodulating, and low and high nodulating plants in pigeonpea

A glasshouse screening program was initiated to identify non-nodulating (Nod−) plants in pigeonpea (Cajanus cajan L. Millsp.). A visual rating scale of 1 (minimum nodulation) to 5 (maximum nodulation) was developed that allowed rapid screening of large numbers of plants. The scale correlated significantly (r = 0.89–0.94, P < 0.001, n = 24) with nodule number and nodule mass. No Nod− plants were identified even after screening 100,000 plants involving five cultivars and advanced breeding lines. However, Nod− plants were obtained from F2 populations of six different crosses. Progeny of these selections when selfed to F3 or to F5 remained Nod−. Plants with a low and high capacity for nodulation were also identified within particular cultivars and advanced breeding lines. After two cycles of pure line selection in the glasshouse progenies of selected materials maintained their relative nodulation ratings when planted in a field of low mineral N (about 10 mg kg−1 soil)

Genetic control of hydrogen sulfide retention in Saccharomyces cerevisiae

The ability to retain hydrogen sulfide (H2S) inSaccharomycescerevisiae is under nuclear gene control. Mutants with the ability to retain greater amounts of H2S than the parent have been isolated and characterised

Genetics of nonnodulation in the new nonnodulating selection of chickpea

Nonnodulating (Nod-) legumes are valuable reference plants for studies on quantification of biological nitrogen fixation. Several such Nod- chickpea genotypes have been identified at ICRISAT and elsewhere, and the inheritance of the Nod- trait worked out in some of them. The present study was undertaken to determine the genetics of nonnodulation in the newly identified Nod- mutants, and the genetic relationship among these and the ones reported earlier. Five new Nod- mutants were crossed with their Nod+ parents. These, and two previously reported Nod- mutants were also crossed among themselves. Parents and the F1, F2, and backcross progenies of the above crosses were inoculated with a mixture of rhizobial strains, and tested for the presence or absence of root nodules in the greenhouse. A single recessivegene was found to control nonnodulation in all but two mutants. Similarly, genetic complementation to produce nodules was observed in most mutant '' mutant crosses. Accordingly, six parents were classified into four allelic groups, and two new nonnodulation genes were identified. Further studies have been proposed to resolve some of the anomalies in segregation ratios. This paper also reports breakdown of the nonnodulation trait in two of the seven Nod- lines, PM 233 and ICC 5003 M

A New Gene that Controls Root Nodulation in Chickpea

Non-nodulating (Nod-) genotypes are an important genetic resource for studies of legume-rhizobium symbiosis. Investigations were carried out to determine the host genetic control of nodulation in two newly identified Nod- chickpea (Cicer arietinum) genotypes, Annigeri NN and Rabat NN, and the genetic relationship between these and other known Nod- genotypes. Annigeri NN and Rabat NN were crossed with each other, with their respective wild-type parents Annigeri (desi) and Rabat (kabuli), and with already known Nod- mutants P319-1 NN and PM233. The parents, F1, F2 and backcross progenies of the crosses were tested for nodulation by mean of a mixture of rhizobial strains in the greenhouse. Chi-square tests were conducted on the crosses to examine genetic hypotheses of monogenic and digenic inheritance. Genetic analyses of Nod- × Nod+ crosses showed a monogenic recessive gene action for non-nodulation in both Annigeri NN and Rabat NN. Studies of Nod- × Nod- crosses indicated that the same gene controls root nodulation in Annigeri NN and P319-1 NN, and that this gene is different from the ones controlling the Nod- trait in Rabat NN and PM233. These results implied that the recessive gene controlling non-nodulation of roots in Rabat NN is different from the ones earlier identified in PM233, P319-1 NN and Annigeri NN. A new gene symbol, rn8, is proposed to be assigned to the locus producing the Nod- phenotype in Rabat NN. This is the first report of a non-nodulating gene in kabuli chickpea

Studies on Soil and Rhizosphere Populations of Rhizobium Sp. Nodulating Cicer Arietinum

Usin a plant Infection d l l u t l o n method developed at ICRISAT for count ? ng chickpea rhlzobia the population of chickpea Rhizobiun has been studied i n Alfisols, Vertisols and Entisols. Sane of the soil samples collected from traditional chickpea growing areas have been found to have low populations of this specific Rhi obium Rhlzobium numbers de8c e ased wi th depth i n a Vertisol from + ; s o i l at [T-IS an to 1 per g s o i l at 90-120 cm. A 100-fold decrease in populat Ion was recorded when wet- 1 and paddy f 01 1 wed chickpea. Of flve ICRISAT mandate crops (sorghum, millet, groundnut, chickpea and plgeonpea) i n pot culture, chickpea roots are most stitnulatory t o the ~~ultlplicatioonf chickpea rhlzobia