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Erratic rainfall often results in intermittent drought and/or waterlogging and limits maize (Zea mays L.) productivity in many parts of the Asian tropics. Developing climate-resilient maize germplasm possessing tolerance to these key abiotic stresses without a yield penalty under optimal growing conditions is a challenge for breeders working in stress-vulnerable agro-ecologies in the region. Breeding stress-resilient maize for rainfed stress-prone ecologies is identified as one of the priority areas for CIMMYT-Asia maize program. We applied rapid cycle genomic selection (RCGS) on two multiparent yellow synthetic populations (MYS-1 and MYS-2) to improve grain yield simultaneously under drought and waterlogging conditions using genomic-estimated breeding values (GEBVs). Also, the populations were simultaneously advanced using recurrent phenotypic selection (PS) by exposing them to managed drought and waterlogging and intermating tolerant plants from the two selection environments. Selection cycles per se (C1, C2, and C3) of the two populations developed using RCGS and PS approach and their test-cross progenies were evaluated separately in multilocation trials under managed drought, waterlogging, and optimal moisture conditions. Significant genetic gains were observed with both GS and PS, except with PS in MYS-2 under drought and with GS in MYS-1 under waterlogging. Realized genetic gains from GS were relatively higher under drought conditions (110 and 135 kg ha−1 year−1) compared to waterlogging (38 and 113 kg ha−1 year−1) in both MYS-1 and MYS-2, respectively. However, under waterlogging stress PS showed at par or better than GS as gain per year with PS was 80 and 90 kg ha−1, whereas with GS it was 90 and 43 kg ha−1 for MYS-1 and MYS-2, respectively. Our findings suggested that careful constitution of a multiparent population by involving trait donors for targeted stresses, along with elite high-yielding parents from diverse genetic background, and its improvement using RCGS is an effective breeding approach to build multiple stress tolerance without compromising yield when tested under optimal conditions

The screening of fifty five CIMMYT maize hybrids was carried out to estimate the genetic diversity which was evaluated undermanaged waterlogged or excess soil moisture condition, indicated presence of considerable diversity. The experiment was conducted in an alpha lattice design with two replication and phenotypic data were analyzed using fifteen agro-morphological traits. The fifty five maize single cross hybrids grouped into eight clusters based on Mahalanobis D2 statistic. Among them cluster I accommodated maximum number of inbred lines (41) followed by cluster V (8). Presence of six solitary clusters indicated larger genetic diversity. The character plant height showed highest contribution towards genetic divergence followed by number of kernel per row, ear height, number of rows per ear, grain weight per plot and 100 seed weight. Based upon the divergence studies suggesting crossing may be made between genotypes of cluster II (P3502) and V (ZH17505, ZH17507, ZH17497, ZH15567, ZH15557, ZH15564, ZH15563 and ZH15562), and the hybrid in these cluster could be used as donor parents for new double cross maize hybrid development for improving yield under water logging condition.

In the present investigation 25 genotypes of maize collected from different sources were characterized for the soluble seed proteins using sodium dodecyl sulphate polyacrylamide gelelectrophoresis (SDS-PAGE). The total protein bands were separated on 12% polyacrylamide gel using standard protocols. Highest number of bands observed was 14 in inbred HUZQPM-1.Highest coefficient of similarity matrix was0.69whereas lowest was 0.04. The dendrogram prepared by using UPGMA clustering method separated the whole genotypes into two main groups; I and II. On the basis of present investigation, it is observed that there is low variability present among quality protein maize inbreds.