Single Cross Hybrid

Introduction Considerations for Hybrid Seed Production Advantages
Seed Production Technology Post Harvest Management Economics of seed production

Introduction

Maize occupies an important place in world agriculture. It is grown in more than 150 countries. The major producing countries are USA , China ,     Brazil , Mexico , France and India . It is third most important cereal crop in India after rice and wheat that occupied about 8.12 million hectares having production of 19.77 million tonnes with average productivity of 2.4 tonnes/ha during 2007-08 (Fig. 1) 

Genotype Development Strategy vis-a-vis Area, Production, Productivity Scenario of Maize in India

Period

Maize Breeding Strategies

1950-60

Land races

1960-67

Double cross (DC)

1967-71

Composite

1971-89

Composite and Double top cross (DTC) I DC

1989-2000

Single Cross Hybrid (SCH)/DC / Three Way cross (TWC) and composites

2000-06

SCH/TWC/DC and composites

2006-onwards

Single Cross Hybrids


                     

 

Year

Area (m ha)

Production (m t)

Productivity (kg ha_1)

2006-07

7.89

15.10

1912

2007-08

8.12

19.77

2435

Increase (%)

2.83

30.93

27.35

 

 

 

 

 

                    

                                               Figure 1: Trends of area, Production and productivity of maize in India

 

All India Coordinated Research Project (AICRP) on maize was launched in 1957 with the objective to develop and disseminate genetically superior cultivars and crop production/ protection technologies. Since 1961, a total number of 118 hybrids have been released under this project. Indian maize programme has now given focus on single cross hybrids and since 1990, a total number of 42 single cross hybrids of normal maize, quality protein maize and baby corn have been released (Annexure-I). During 2007-08, maize production increased by 31 % and productivity by 27% over the last year (Fig. 1). The spectacular growth in maize production may be attributed to the development of single cross hybrids which cover about 20% of the total maize area.

 

Single cross hybrid maize varieties are the first generations (F1) from crosses between two inbreds that are genetically dissimilar. Seed production of single cross hybrid requires only two parents and one season. Seed production technology is almost similar throughout country except few location specific technologies. Seed growers may consult local maize breeders of All India Coordinated Research Project on maize (AICRP on maize) for getting parental lines of particular single cross hybrid suited for that location. Network of AICRP centres on maize is given in Map 1.

                                    

                                    Map 1. Maize Research Zones and Centres of the DMR  

Region specific seed production/Seed Village concept

To meet the increasing demand of quality seed across the country, the seed production should be region specific a "Seed ViIlage" with program concept that faciIitates in-

·        overcoming isolation problem

·        with ease in monitoring

·        maintaining genetic purity of the seed

·        reduction in cost of production

·        timely availability of seed

·        reduction in cost of transportation

·        improving farm profitability

·        employment generation to rural masses

·        earning foreign exchange as the cost of single cross hybrid (SCH) maize seed production is lowest in developing and under developed world due to low cost of cultivation because of cheaper labour

Prerequisite of single cross hybrid seed production

·         Proper site selection-avoid the sites where preceeding crop was maize

·         Fertile and quality land with good quality and assured irrigation

·         Productive, uniform and genetically diverse inbred lines

·        Proper isolation distance

·        Technology (Package of practices) for hybrid seed production

·        Technically experienced manpower

·        Stress free season

  

Characteristics of good seed parent (female)

·        Productive

·        Strong

·        Long cobs with complete exertion (Photo 1)

·        Low cob placement

·        Lax tassel

·        Shorter Anthesis Silking Interval (ASI)

·        Nutrient responsive

·        Stay green trait

·        Erect leaves

·        Resistant/tolerant to biotic and abiotic stresses

·        Strong root system

                                            

                                                         Photo 1. Long cob with complete exertion

Characteristics of good pollen parent (male)  

       ·        Lax tassel, long main branch with few secondary branches (Photo 2)  

·        Long duration of pollen shedding

·        Taller than female parent

·        Attractive grain colour

·        Strong plant resistant to lodging with better root system

·        High yield potential

·        Resistant/tolerant to biotic and abiotic stresses

                    Photo 2. Good pollen parent (Male)