Use of molecular marker diversity to increase forage yield in timothy (Phleum pratense L.)

Abstract

1The aim of this study was to investigate genetic distances (GDs) based on molecular 2 markers in relation to forage yield improvement in timothy syn1 and polycross progenies.

Genotype selection for physiological responses of drought tolerance using molecular markers in polycross hybrids of orchardgrass

“…Yield superiority of HMD group progeny over the LMD group progeny (69.60%) and control (48.10%) at drought stress conditions is a promising indication deserving close attention in the breeding programmes. The presence of significantly increased forage yield in Syn1 progeny from parents selected for HMD is in agreement to findings in perennial ryegrass, tall fescue and timothy (Amini et al, ; Ghesquiere et al, ; Kolliker et al, ; Tanaka et al, , ). Since yield stability is one of the main breeding objectives in breeding for stress environments (Einfeldt, Ceccarelli, Grando, Gland‐Zwerger, & Geiger, ), higher values of STI and YSI in HMD group progeny compare to LMD group progeny and the control is quite remarkable and implies that HMD group progeny had greater buffering capacity against reduction in yield under drought stress.…”

“…In other words, heterosis probably exists due to different allelic combinations at particular loci in each parent which when brought together in hybrid combination, complement each other, resulting in heterosis expression. Moreover, progeny are able to produce diverse allelic products which increase the overall performance (Geleta, Labuschagne, & Viljoen, 2004;Pandey et al, 2015;Tanaka et al, 2013). Lower fitness of progeny from parents with LMD was F I G U R E 2 Cluster analysis of four polycross groups with contrasting levels of diversity under normal irrigation (a) and drought stress conditions (b).…”

“…Studies of phenotypic and molecular diversity in relation to hybrid performance have been undertaken in several forage grasses. Investigations in timothy, perennial ryegrass and tall fescue have shown that the genetic diversity of parents captured by molecular markers, was significantly correlated with hybrid performance (Amini, Mirlohi, & Majidi, 2016;Amini, Mirlohi, Majidi, Shojaieefar, & Kollilker, 2011;Ghesquiere, Muylle, & Baert, 2013;Kolliker, Boller, & Widmer, 2005;Liu, 2015;Tanaka et al, 2015;Tanaka, Tamaki, Ashikaga, Fujii, & Yamada, 2013).…”

Marker‐Based Paternity Test in Polycross Breeding of Timothy

“…Another reason for unbalanced selection may be that only progeny plants derived from a particular parental combination tend to be selected due to affinity between maternal and paternal parents exhibiting specific combining ability and/or inbreeding depression. The significant correlation between yield performance of polycross progenies and marker‐based genetic distances shown in a previous study using Polycross D (Tanaka et al, 2013) supports this as a cause of unbalanced paternal selection in Polycross D. However, this cannot apply to Polycross B (data not shown). Unequal polycross mating may also cause unbalanced frequency of paternal parents in a polycross population.…”

“…II (Table 2) was described in a previous study (Exp. 2 in Tanaka et al, 2013). Briefly, cumulated DMYs (Mg ha −1 ) of 41 progenies from Polycross D, together with check cultivars (‘Nosappu’, ‘Aurora’, and ‘Hokusei’) as comparative controls, were evaluated over 2 yr (2002–2003) at the KAES.…”