Abstract
Chickpea (Cicer arietinum L.) is predominantly an indeterminate plant and tends to generate vegetative growth when the ambient is conducive for soil moisture, temperature and certain other environmental conditions. The semi-determinate (SDT) types are comparatively early, resistant to lodging and found to be similar in their yield potential to indeterminate (IDT) lines. Indeterminate and semi-determinate genotypes are found to be similar during early stage, which makes it difficult to distinguish between them. Thus, there is a need to identify molecular markers linked either to indeterminate or semi-determinate plant types. The present study was carried out to study the genetics of semi-determinacy and identify molecular markers linked to stem growth habit. The study was undertaken in the cross involving BG 362(IDT) × BG 3078-1(SDT). All F1 plants were indeterminate, which indicates that indeterminate stem type is dominant over semi-determinate. In further advancement to F2 generation, F2 plants are segregated in the ratio of 3(Indeterminate): 1(Semi-determinate) that indicates that the IDT and SDT parents which are involved in the cross differed for a single gene. The segregation pattern observed in F2 is confirmed in F3 generation. The parental polymorphic survey was undertaken for molecular analysis using total of 245 SSR markers, out of which 41 polymorphic markers were found to distinguish the parents and were utilized for bulked segregant analysis (BSA). The segregation pattern in F2 indicates that the IDT (Indeterminate) and SDT (Semi-determinate) parents which are involved in the cross differed for single gene. The segregation pattern of F2 and F3 derived from the cross BG 362 (IDT) × BG 3078-1 (SDT) confirmed the genotypic structure of the newly found SDT genotype BG 3078-1 as dt1dt1Dt2Dt2. Three SSR markers TA42, Ca_GPSSR00560 and H3DO5 were found to be putatively linked to Dt1 locus regulating IDT stem growth habit. Our results indicate that the SSR markers identified for Dt1 locus helps to differentiate stem growth habit of chickpea in its early growth stage itself and can be efficiently utilized in Marker Assisted Selection (MAS) for changed plant type in chickpea.
Highlights
Chickpea (Cicer arietinum L.) is predominantly an indeterminate plant and tends to generate vegetative growth when the ambient is conducive for soil moisture, temperature and certain other environmental conditions
The stem growth habit plays a significant role in determining plant architecture, which is of major agronomic importance and specifies plant adaptability to crop cultivation as well
The SDT genotype BG 3078-1 flowered in 56 days and matured in 119 days after sowing (DAS) whereas the IDT genotype BG 362 (IDT) flowered in 75 days and reached maturity in 135 D AS11
Summary
Chickpea (Cicer arietinum L.) is predominantly an indeterminate plant and tends to generate vegetative growth when the ambient is conducive for soil moisture, temperature and certain other environmental conditions. In further advancement to F2 generation, F2 plants are segregated in the ratio of 3(Indeterminate): 1(Semideterminate) that indicates that the IDT and SDT parents which are involved in the cross differed for a single gene. The segregation pattern in F2 indicates that the IDT (Indeterminate) and SDT (Semi-determinate) parents which are involved in the cross differed for single gene. Chickpea is predominantly an indeterminate type and tends to generate a vegetative phase, when the temperature, soil moisture and certain other environmental conditions are c onducive[7]. The indeterminate growth allows competition between the vegetative and reproductive phases for assimilation partitioning This promotes low and unstable harvest index leading to low seed yield. The determinate plants carry recessive alleles at both loci in homozygous condition (dt1dt1dt2dt2)[9]
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