Cyto-morphological studies op some species and hybrids in the Eu-Sorghums

Abstract

Important morphological features such as plant height, leaf size and number of leaves, shape of the panicle and sessile spikelets, staminate condition of the pedicellate florets, nature of lemma, colour of the stigmatic surface and seeds etc., were studied in 8 Sorghum species and 10 F1 hybrids between them. Based on the data, interrelationship amongst the species are discussed. Pachytene pairing was complete and apparently normal, followed by regular meiosis at later stages resulting in high pollen stainability and good seed setting in all the parental species except the male sterile “Kafir”. Studies on the pairing properties of the differentially stained regions showed that synapsis starts from the proximal to the distal end and separation of the split chromosomes starts from the distal to the proximal. The interspecific hybrids studied are classified into four types based on pachytene pairing and pollen sterility. 1. normal pairing accompanied by high pollen fertility, 2. normal pairing accompanied by partial pollen sterility. 3. irregularities in the pachytene pairing followed by partial pollen sterility and 4. irregularities in the pachytene pairing accompanied by normal pollen fertility. Suitable explanations are advanced to explain the meiotic aberrations noted in some of the hybrids under study. Cytogenetical mechanisms underlying species differentiation in the Eu-Sorghum species are discussed.