DUS-Based Morphological Evaluation of Sesame (Sesamum indicum L.) Genotypes

Abstract

Sesame (Sesamum indicum L.) seed is an important source of edible oil and are also widely used as a spice. Sesame, the ‘queen of oil seeds,’ is known for its high oil content (50-60%) and quality. Generally, the quality of seed is estimated by varietal purity, including physical and genetic. The varietal characterization, varietal identification and genetic purity assessment are of utmost importance for field functionaries, Certification Officers, Seed Production Officers and Seed Growers for maintaining the quality of the seed. The study aimed to determine the relative extent of distinctiveness, uniformity, and stability of different morphological descriptors in sesame genotypes. In the present investigation, an attempt was made to characterize fifty-six sesame genotypes comprised of fifty advanced breeding lines and six checks using plant morphological traits developed for Distinctness, Uniformity and Stability (DUS) guidelines. The DUS guidelines for sesame were available in the schedule released by the Protection of Plant Varieties and Farmers' Rights Authority (PPV & FRA). The fifty-six sesame genotypes were characterized with twenty morphological characters, including both qualitative and quantitative characters. The study was conducted at the All India Co-ordinated Research Project on Sesame, RARS, Jagtial, during late Kharif 2019. Each genotype was sown in a row of 3 m length with a spacing of 30 × 10 cm. The basal dose of 40:20:20 NPK Kg/ha was applied at the time of sowing, and the remaining 25 kg of nitrogen was applied 30 days after sowing as top dressing. The results revealed that forty-eight genotypes showed medium (2.1 to 4) branching habit, and eight showed profuse branching habit. The study of the hairiness of capsules showed that sesame genotypes can be classified into three categories. The eleven genotypes had absent hairiness, 29 genotypes were observed as sparse, and the remaining sixteen genotypes were recorded as dense hairiness types. Differences were also observed in the arrangement of the capsule; 24 genotypes were found alternate, 31 genotypes were found opposite, and the remaining one genotype was found in a cluster type. Out of twenty morphological, visually assessed DUS descriptors studied, three were found to be monomorphic, while ten were dimorphic, and the remaining characters were polymorphic, which were useful for varietal identification. Morphological characters have been widely used for descriptive purposes and are commonly used to distinguish plant varieties. The study concluded that the use of morphological descriptors in a sequential fashion is useful and convenient to discriminate different varieties. These differences in morphological traits were useful in the identification of individual sesame genotypes.