~ 962 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(5): 962-964 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(5): 962-964 Received: 23-07-2018 Accepted: 25-08-2018 Swathi L Centre for Plant Breeding and Genetics, TNAU, Coimbatore, Tamil Nadu, India C Babu Centre for Plant Breeding and Genetics, TNAU, Coimbatore, Tamil Nadu, India K Iyanar Centre for Plant Breeding and Genetics, TNAU, Coimbatore, Tamil Nadu, India AJ Prabakaran Sugarcane Breeding Institute, ICAR, Coimbatore, Tamil Nadu, India NA Saravanan Sugarcane Research Station, TNAU, Melalathur, Tamil Nadu, India Correspondence Swathi L Centre for Plant Breeding and Genetics, TNAU, Coimbatore, Tamil Nadu, India Assessing the chromosomal stability during cell division in the interspecific hybrids of pearl millet × Napier grass hybrid CO (BN) 5 Swathi L, C Babu, K Iyanar, AJ Prabakaran and NA Saravanan Abstract Pennisetum glaucum, with 2n = 2x = 14 chromosomes and genomes AA and Pennisetum purpureum with 2n = 4x = 28 chromosomes and genomes A’A’BB belongs to two different gene pools are however sexually compatible and undergoes hybridization that favors the introgression of favorable alleles into development of Pearl Millet × Napier (PMN) hybrids. But the major problem lies in their interspecific hybrids that produces sterile pollen grains due to triploidy (2n = 3x = 21). This current study describes meiotic behavior of PMN hybrid CO (BN) 5 of TNAU origin along with its parental lines. Pearl millet parent variety (IP 20594) used as female parent presented normal and regular meiotic behavior with seven bivalents. In Napier parent (FD 437) normal bivalent formation was noticed, however, univalents ranging from 1- 3 and laggards during anaphase-I were also observed in few pollen mother cells. The hybrid, presented a high frequency of abnormalities that were characterized by irregular chromosomal segregation and tetrad formation with micro nuclei. Keywords: Pennisetum, pearl millet, Napier grass, interspecific hybrids and meiosis Introduction Several cultivable species are present are in the family Poaceae, of which Pennisetum is one of the most important genera. Out of approximately, 140 species, Pennisetum glaucum (L.) R. Br. (pearl millet) and Pennisetum purpureum Schumach (Napier grass) are the most important species economically, which are widely used either directly as forage grasses [3] or in genetic improvement of PMN hybrids. The Pennisetum species were reported to have the basic chromosome number (x) as five, seven and eight and based on their ploidy level, the species were divided into three gene pools. The cytogenetic studies in Pennisetum was first made by [19] followed by other researchers [4] [9, 10] . Pennisetum glaucum with 2n = 2x = 14 chromosomes and genomes AA belongs to the primary gene pool and Pennisetum purpureum, an allogamous grass with 2n = 4x = 28 chromosomes and genomes A’A’BB belongs to secondary gene pool [7] . Inspite of their positions in different gene pools with different ploidy levels, they are sexually compatible, thus permitting the introgression of desirable characters from pearl millet and Napier grass on hybridization. Interspecific hybridization between these species had been attained to explore the variability available within these species [14, 15] . The resulting hybrids combines the enhanced dry matter production, high nutritive value, perenniality and good palatability of the Napier grass with good resistance to drought and diseases, forage quality, tolerance to low fertility levels of the soil of pearl millet [18, 24] . However, the major drawback lies in the infertility of the resulting hybrids with triploid condition (2n = 3x = 21 chromosomes). Earlier meiotic studies by [17, 9, 10] recorded the formation of seven bivalents of A and A’ genomes of pearl millet and Napier grass, respectively and seven univalents of B genome from the Napier grass, in the diakinesis stage. These univalent in general displays irregular segregation resulting in the formation of aneuploids, thus resulting in sterility. Several literatures were available on the cytological studies of pearl millet, however very few literatures pertaining to cytological studies of Napier grass and pearl millet Napier hybrids were available. The present study was conducted to understand the cytological behavior of pearl millet Napier grass hybrid, CO (BN) 5 and its parental lines. Materials and methods The hybrid CO (BN) 5 was developed by crossing Napier line (FD 437) as male parent and pearl millet (IP 20594) as female parent, at Tamil Nadu Agricultural University, Coimbatore