**3.2 Hybridization**

It is a very common breeding method utilized in development of a crop variety. Hybridization is a process in which crosses are made between two varieties of same species (inter-varietal hybridization); between two different species of same genus (inter-specific); between two different genera of same family (inter-generic). For self pollinated crop like rice, hybridization program is followed via Pedigree selection, Bulk Method, and Convergent Breeding to develop new varieties. Introduction of dwarfing gene and development of hybridization techniques in 1960s, augmented the Basmati development program Siddiq et al. [7] and other aromatic varieties too. Short, medium and long grained aromatic rice were developed at


#### **Table 5.**

*Aromatic varieties developed through pureline selection.*


#### **Table 6.**

*Aromatic varieties developed through hybridization in India.*

different agricultural research Institution in India (**Table 6**). PB1 is the first, high yielding, and semi-dwarf Basmati variety, developed through convergent breeding method in 1989 [9].

Outstanding achievements of Hybrid rice breeding in China encouraged Indian plant breeders to employ hybrid breeding in aromatic rice too. In India, hybrid breeding in aromatic rice was initiated first in Basmati germpalsm. CMS lines like: **Pusa 3A** and **Pusa 4A**, were developed at IARI (Indian Agriculture Research Institute, New Delhi) from PB-1. Several high yielding varieties viz., Pusa Sugandha-2, Pusa Sugandha-3, and Pusa Sugandha-5 were developed using crosses of Pusa 3A and Haryana Basmati-1 [7]. Sugandha is a Hindi word meaning "Scented". In 2001, IARI developed first *hybrid aromatic* rice (PRH10) in world. PRH-10 was developed by crossing Pusa Sugandha with Pusa 6A (CMS line).

#### **3.3 Mutation breeding**

Mutation breeding is a useful method to produce genetic variability in crop. In mutation breeding, whole plant/plant part/seed are subjected to mutagen (physical or chemical). This method has been widely applied in developing new varieties in different crops including rice. In aromatic rice, mutation breeding is used to bring desirable change in quality traits. Many mutants line have been developed from several aromatic rice genotypes including Basmati (especially Basmati-370) but only few of them are cultivated. In India mutant lines have been developed in genotypes viz., Kalimoonch-6, Bindli, Kamal Local, Type-9, NP-49, T412, Kalanamak, Gobindbhog, Badshapasand and Basmati-370. Mutants showing certain desirable trait (dwarf stature, lodging resistance, early maturing) are conserved to be used in future breeding program. One such institute is NRRI, Cuttack, India which is maintaining more than 100 mutant lines having certain desirable traits of aromatic rice. Geetanjali and ADT 41 aromatic rice varieties

were developed at NRRI; these are mutant lines of Basmati-370. A-201 aromatic variety of USA was developed by using PI457920 mutant; this mutant was developed from Basmati-370 of Pakistan.
