Male-sterile seed parents for the [Pennisetum glaucum (L.) R. Sr.] breeding of landrace-based topcross hybrids of pearl millet for the arid zone. III. Matching A-lines and specific target environments

Abstract

Growing environments of pearl millet [Penn/setum glaucum (L.) R. Sr.] in the Indian arid zone are quite heterogeneous both in terms of environmental stresses and farming system needs. In this paper we described main target environments for pearl millet breeding programs within the arid zone, and then attempted to identify male-sterile (A) lines for developing suitable landrace-based topcross hybrids (TCHs) and conventional hybrids for the identified target environments. Target environments were defined as extreme stress, moderate stress and favourable environments based on the available environmental resources for, and limitations to, crop production in each target zone. TCHs based on 39 A-lines were clustered into five clusters for grain, stover and biomass yields, yield stability, responsiveness to environment, downy mildew and drought resistance and several other variables. The suitability of individual A-lines for different target environments was judged by their ability to produce TCHs with the adaptive traits considered as most important for each target environment. None of the A-lines produced hybrids that were equally well-adapted to all the three types of environments; most of the A-lines produced hybrids that showed a contrasting adaptation pattern to the different target environments. The A-lines ICMA 93111, ICMA 94555, ICMA 95111, HMS 9A and CZMS 44A produced highly stable dual purpose hybrids; and 842A, ICMA 95444, ICMA 97111, ICMA 97444 and 843A grain hybrids that were suitable for extreme stress environments. Hybrids made with ICMA 97333, ICMA 93111, ICMA 95555, ICMA 96333, 842A, ICMA 91444 and ICMA 92666 were suitable for moderate stress environments in that they proved high yielding, moderately stable and responsive hybrids to better environments. On the other hand, hybrids based on 5054A, ICMA 88006, ICMA 95222, ICMA 92333, ICMA 92444, ICMA 94555 and ICMA 97333, ICMA 96222, ICMA 97111, ICMA 91444 and ICMA 95444 were identified as most desirable for favourable environments. Utilisation of A-lines and their respective maintainers has been discussed for developing suitable hybrids and new parental lines of hybrids for arid zones.