Genetic improvement of breeding materials in tropical and sub- tropical maize

Abstract

In the present study, 122 maize local cultivars and adapted exotic germplasm from Thailand were used to develop open pollinate varieties (OPVs) using modified ear-to-row scheme, top-cross or test-cross programmes. Ten new maize OPVs with distinct characters were created based on the precise breeding objectives and directional design. The selection of breeding materials was based upon three factors: elite performance, broad adaptability, and genetic diversity. The synthesizing system provided four features: genetic mixing and recombination, equal comparable genetic contribution, mild selection pressure, and maximum intermating for genetic equilibrium (i.e., the female traits were close for the genetic com-positions). Subsequently, Suwan 1 composite and its deritives (Suwan 2, Suwan 3 composite, Suwan 5 and KS24 synthetics), KS6 and KS28 synthetics with the dent type of different origins, and Caripeno DMR composite, KS23, and KS27 synthetics with the dent type of Non-Suwan 1 origin were developed. These OPVs had been improved for 2~13 cycles using S1 recurrent selection method. About 50 inbred lines were developed from these OPVs, and 16 elite single (three-way) crosses were combined and released from these inbred lines. At present, at least one parental inbred line of all the tropical hybrids was derived from Suwan (KS) germplasm in Thailand. Based on the theory of the synthesizing OPVs and developing inbred lines, this paper discussed the genetic moderate diversity, relationship, heterotic group, and patterns for synthesizing OPVs, and inspiration for composed OPVs to heterosis breeding.

Comparative Transcriptome Analysis Uncovers Genes and Pathways Relating to Downy Mildew Resistance in Isabgol (Plantago ovata Forsk.)

“…Development of DM resistant varieties becomes a challenge for Isabgol breeders. Characterization of the mechanism underlying DM resistance and the breeding new varieties with resistance and good agronomic traits have been very difficult because resistance to DM is a complex trait and controlled by polygenes [20][21]. Furthermore, current understanding of DM resistance mechanism in Isabgol at the enzyme, gene and regulatory levels is incomplete.…”

“…Similarly, Kotwal et al[34] also found Isabgol transcripts largely aligning to Erythranthe guttata genome. Earlier, Albach et al[49] and Melotto-Passarin et al[50], documented the phylogenetic closeness of the family SI and RI) samples demonstrated the involvement of PP fungal transcripts in compatible interaction with host[16][17][18][19][20][21][22][23][24][25][26][27]. Further analysis PP fungal transcripts may help understand the host pathogen interaction pathways.Gene ontology (GO), is a useful tool to annotate large number of genes and their products and analyze their functions.…”