<div>Pigeonpea has 2n= 2x= 22 chromosomes with length ranging from 5.73&plusmn;1.15 &mu;m to 10.92&plusmn;2.69 &mu;m. The largest long arm of chromosome pair (q) was 6.22&plusmn;1.05 &mu;m, while the shortest measured 3.37&plusmn;0.83 &mu;m. The longest short arm chromosome pair was 4.70&plusmn;1.65 &mu;m, while the shortest measured 2.37&plusmn;0.43 &mu;m. Metacentric and submetacentric chromosomal shapes exist in pigeonpea, but metacentric dominating. Pigeonpea&rsquo;s karyotypic formula is 2n= 2x= 9m+2 sm. In pigeonpea, regardless of maturity groups, the main and foremost goal is to breed for higher yield/area/time. Resistance to diseases including wilt, sterility mosaic, phytophthora and alternaria blights, as well as insect pests like pod borers and pod flies, is being bred for. Resistance to abiotic stresses like drought tolerance can be achieved by osmotic adjustment (OA), dehydration tolerance and relative water content (RWC). Reduced Na and Cl translocation from root to stem, osmoprotectants and the optimal leaf area index (LAI) for salinity tolerance. Many outstanding varieties has been developed in pigeonpea through germplasm selection, pedigree breeding, mutation breeding and Heterosis breeding.</div>


<p>Cytogenetics and Crop Improvement Studies in Pigeonpea [<em>Cajanus cajan</em> (L.) Millsp.]: A Review</p>


<p>The karyological investigation using 16 purebred Sahiwal and 16 Jersey X Sahiwal cattle (8 males and 8 females of each genetic group) revealed the diploid chromosome number to be 60. All the 29 pairs of autosomes were acrocentric, while the X &ndash; chromosome was sub-metacentric in both the genetic groups. Acrocentric Y chromosome of Sahiwal differed from small submetacentric chromosome of Jersey X Sahiwal cattle in its morphology. The relative length of autosomes ranged from 1.74 &plusmn; 0.01 to 5.28 &plusmn; 0.02 in Sahiwal and from 1.72 &plusmn; 0.01 to 5.26 &plusmn; 0.02 in Jersey X Sahiwal crosses. X &ndash; Chromosome was the second largest chromosome in both the genetic groups. The contribution of &nbsp;X and Y chromosomes to the total genome were 5.07 and 1.99 per cent to the total genome in Sahiwal and 5.06 and 2.20 per cent &nbsp;in Jersey X Sahiwal cattle, respectively. The arm ratio, centromeric index and morphological index for the X-chromosome of Sahiwal and Jersey X Sahiwal cattle were 1.89, 0.35, 2.87 and 1.84, 0.36, 2.76, respectively. The arm ratio, centromeric index and morphological index for the Y-chromosome of Jersey X Sahiwal cattle were 1.63, 0.35 and 1.41, respectively.</p>


Cytogenetics and Crop Improvement Studies in Pigeonpea [Cajanus cajan (L.) Millsp.]: A Review

Comparison of chromosomal architecture of Sahiwal and crossbred Sahiwal cattle