<p>The research deals with cytological investigation on pre and post-fertilization barriers in <i>Cajanus cajan</i> (Pigeonpea variety CO 8) and wild species <i>C. cajanifolius</i> and the pollen fertility assessment and in-vitro pollen germination in <i>Cajanus scarabaeoides</i>. Pollen-pistil interaction in wide crosses could be analysed by aniline blue technique. At 2 HAP and 24 HAP. The higher and lower pollen germination percentage was found in direct and reciprocal crosses of two pigeonpea species <i>C. cajanifolius</i> and <i>Cajanus scarabaeoides</i> respectively. In direct and reciprocal cross, mean pollen germination percentage was 73.6 and 60.4% respectively. In direct cross, pod set percent is very less, due to post-zygotic fertilization barrier. In reciprocal cross, there is no pod set which indicates pre-zygotic fertilization barrier. Acetocarmine pollen fertility test reveals that <i>Cajanus cajan</i> (CO 8) is more fertile than <i>Cajanus cajanifolius</i> and hence the former one being good pollen-producing parent in terms of fertility. The best medium for in vitro pollen germination for <i>Cajanus scarabaeoides</i> isBrewbaker and Kwack medium (20% sucrose, 100mgl^− 1 boric acid, 300mg^− 1 calcium nitrate, 200mg^− 1 magnesium sulphate and 100mg^− 1 potassium nitrate). The findings were compared and strategies to alleviate the pre- and post-fertilization barriers and revealed that chromosomes have a degree of homology between <i>C. cajanifolius</i> and <i>C. cajan</i>, which is further aided by their quick crossability and production of a fertile hybrid.</p>