Introduction
Varieties of crops with no exception of dolichos bean are considered as intellectual properties as their development is based on sound genetic principles, selection skill and resources. Further, although they are developed from genetic resources that have evolved in nature, they represent a considerable reorganization of gene combinations with an enhanced economic value. Thus, the development of crop varieties requires considerable resources, time and intellectual input. The individual/agencies/institutions other than the originator/developers can easily multiply and commercialize crop varieties, especially pure-line varieties which are the only cultivar option in dolichos bean and derive economic benefits from them. These activities will greatly reduce economic benefits to the originators of crop varieties. Seeking legal rights on crop varieties is the best and the only way to protect them from an unlawful claim of their origin/development and deriving economic benefits from them. Therefore, almost all the nations including India have enacted appropriate laws to protect the rights of originators of crop varieties. In India, seeking legal rights on crop varieties under Protection of Plant Varieties and Farmers Rights (PPV&FR) act – 2001 (http://www.plantauthority.gov.in) requires establishment of their distinctiveness (D), uniformity (U) and stability (S). PPV & FR act regulations consider morphological and physiological traits including disease and insect pest resistance for establishing DUS (Pratibha et al., Reference Pratibha, Sanjeev and Dhillon2004). The objective of the present study is to establish morphological descriptors-based DUS of advanced breeding line (ABL), elite germplasm accessions and released varieties.
Experimental
The material for the study consisted of five genotypes which include two photoperiod insensitive (PIS) released varieties, HA 3 and HA 4 (referred to as reference varieties), one PIS ABL, i.e. HA 11-3 and two photoperiod sensitive (PS) elite germplasm accessions, Kadalavare (KA) and GL 66 (referred to as candidate varieties) (Vaijayanthi et al., Reference Vaijayanthi, Ramesh, Byregowda, Mohan, Keerthi and Reena2015). The seeds of five genotypes were sown in randomized complete block design with three replications at the experimental plots of the Department of Genetics and Plant breeding, College of Agriculture (CoA), University of Agricultural Sciences (UAS), Bengaluru, India during 2016 rainy season. Data on dolichos bean 25 characterization descriptors (online Supplementary Table S1) (Byregowda et al., Reference Byregowda, Girish, Ramesh, Mahadevu and Keerthi2015) which include eight vegetative traits, five inflorescence traits, five fruit traits and seven seed traits were recorded on 25 plants randomly selected from each of the five genotypes.
Criteria to assess DUS of candidate varieties: As per the article 15.3 (b) of PPV & FR Act (http://www.plantauthority.gov.in), a candidate variety was considered distinct if it is distinguishable from any other variety or a reference variety by at least one trait. The reference variety is the one whose existence is a matter of common knowledge. The uniformity of candidate varieties was assessed based on the occurrence of acceptable numbers of off-types within a candidate variety in self-pollinated crops [article 15.3 (c) of PPV & FR Act] (online Supplementary Table S2). Off-types are those plants which are clearly distinguished from the candidate variety in the expression of the traits that are used to establish distinctness. As dolichos bean is a predominantly self-pollinated crop (Kukade and Tidke, Reference Kukade and Tidke2014), in the present study, numbers of off-types among 25 randomly sampled plants from each of the three candidate varieties for the traits used to establish distinctness were counted. The candidate varieties with absence/permissible numbers of off-types were regarded as uniform. The candidate varieties are considered stable if the traits which are used to establish their distinctness remain unchanged after repeated propagation [article 15.3 (d) of PPV & FR Act]. It is not usually possible during a period of 2 or 3 years to perform test of stability that produce results as certain as the testing of distinctness and uniformity does. Hence, generally when candidate varieties are found uniform, they are also considered stable. Therefore, in the present study, the candidate varieties which were found uniform were deemed stable.
Discussion
Distinctness of candidate varieties from the reference variety, HA 3: Plant morphological characters have been recognized as the universal and undisputed descriptors for DUS testing of crop varieties. In the present study, the candidate varieties were distinct from HA 3 only for 12 of the 25 descriptors (Table 1). The candidate variety, HA 11-3 was distinct from HA 3 for leaf colour, fresh pod curvature and fresh pod pubescence. Of these traits, fresh pod curvature is the most reliable descriptor for assessing distinctness between HA 11-3 and HA 3. Similarly, KA, another candidate variety differed from HA 3 for leaf colour, leaf hairiness, growth habit, branch orientation, fresh pod curvature, fresh pod pubescence and fresh pod constriction (Table 1). KA and HA 3 could be more easily distinguished using growth habit and fresh pod curvature as they are easily assayable than others and exhibit simple oligogenic (1–3 genes) inheritance (Keerthi et al., Reference Keerthi, Ramesh, Byregowda, Mohan, Rajendra Prasad and Vaijayanthi2015). The candidate variety, GL 66 differed from HA 3 for stem pigmentation, leaf colour, leaf hairiness, growth habit, branch orientation, flower bud colour, standard petal colour, wing petal colour, fresh pod pubescence, fresh pod constriction and dry seed colour (Table 1).
Table 1. Distinctness of candidate varieties (HA-11-3, Kadalavare and GL 66) with reference varieties (HA 3 and HA 4) based on morphological descriptors
Distinctness of candidate varieties from the reference variety, HA 4: The candidate variety, HA 11-3 differed from HA 4 for only fresh pod pubescence, while the candidate variety, KA differed from HA 4 for leaf colour, leaf hairiness, growth habit (Fig. 1), branch orientation, fresh pod curvature, fresh pod pubescence and fresh pod constriction (Table 1). The candidate variety, GL 66 differed from HA 4 for stem pigmentation, leaf hairiness, growth habit, branch orientation, flower bud colour, standard petal colour, wing petal colour, fresh pod curvature, fresh pod pubescence, fresh pod constriction and dry seed colour (Table 1). Of these traits, stem pigmentation should be the obvious choice for establishing distinctness of GL 66 from HA 4 as it exhibits stable mono-genic (Raut and Patil, Reference Raut and Patil1985) or trigenic (Rao, Reference Rao1987) inheritance.
Fig. 1. Photographs of a candidate (Kadalavare) and a reference variety (HA 4).
Uniformity and stability of candidate and reference varieties: According to the article 15.3 (c) of PPV & FR Act (http://www.plantauthority.gov.in), the complete absence of off-types within each of the three candidates and two reference varieties indicated their uniformity. Because of their uniformity, they are deemed stable according to the article 15.3 (d) of PPV & FR Act.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/S147926212000009X.
