Novel Sources of Resistance to Root-Lesion Nematode (Pratylenchus thornei) in a New Collection of Wild Cicer Species (C. reticulatum and C. echinospermum) to Improve Resistance in Cultivated Chickpea (C. arietinum).

Pratylenchus thornei, a nematode species that feeds and reproduces in chickpea (Cicer arietinum) roots, is widespread throughout the Mediterranean basin and Indian subcontinent. In Australia, it can cause yield losses up to approximately 25% of intolerant chickpea cultivars. Potential for improvement has been hindered by the narrow genetic diversity of cultivated chickpea and a limited world collection of original wild Cicer spp. in the primary gene pool, consisting of 18 C. reticulatum and 10 C. echinospermum accessions. Recently, collections of C. reticulatum and C. echinospermum from Turkey have substantially increased the number of accessions. This study evaluated 133 C. reticulatum and 41 C. echinospermum accessions from the new collection for resistance to P. thornei under controlled conditions in repeated glasshouse pot experiments. The aim of the study was to identify accessions with resistance superior to that currently available in Australian germplasm. Both wild Cicer spp. were found, on average, to be more resistant to P. thornei (P < 0.001) than C. arietinum. Combined analyses across experiments to determine genetic rankings showed that 13 (7%) wild accessions were significantly more resistant than the most resistant C. echinospermum reference ILWC 246, while another 40 (23%) accessions were significantly more resistant than the least susceptible Australian chickpea cultivar PBA Seamer. Mean P. thornei population densities differed significantly between collection sites in Turkey and within each of the genetic population groups. The sites Kayatepe and Baristepe1, and genetic population groups Ret_A and Ret_F associated with sites Oyali and Baristepe1, produced the lowest P. thornei population densities. This is the first report assessing the resistance to P. thornei of this new collection which offers novel sources of P. thornei resistance and untapped genetic diversity valuable for international chickpea breeding programs to exploit.

Greater emergence force and hypocotyl cross sectional area may improve wheat seedling emergence in sodic conditions.

Surface crusting of sodic soils is a major problem in the semi-arid tropics when rapid drying after sowing follows light showers, leading to reduced seedling emergence and grain yield. The magnitude of the force exerted by germinating seeds affects the ability of the seedlings to rupture the crust and emerge. This study aimed to determine whether the seed germination and seedling emergence force of wheat (Triticum aestivum L.) seedlings vary among different genotypes at different sodicity levels. Germination and emergence force of seedlings of four wheat genotypes was determined in assays using four solutions with sodium adsorption ratio (SAR) values ranging from 0 to 60. Seed germination and seedling emergence force varied between genotypes at different sodicity levels, with the emergence force of the coleoptile correlated to the cross sectional area of the hypocotyl. The results suggest that the selection of wheat genotypes with rapid germination, higher seedling emergence force and larger hypocotyl cross sectional area, offers a strategy to improve seedling emergence in crusted sodic soils.

Dataset on seed details of wheat genotypes, solution treatments to measure seedling emergence force and the relation between seedling force and strain.

The seed details (weight, vigor) and germination rate of 16 wheat (Triticum aestivum) genotypes in a non-limiting conditions were measured. The dataset presents seed germination rate and seed vigor of 16 wheat genotypes. The dataset also presents the concentrations of the cations to create solution treatments of various sodium adsorption ratio (SAR) and ionic strength (I). Finally, dataset presented a figure of the experimental design to measure seedling emergence force of wheat genotypes. The image of the setup and the relation between strain and force have been presented here to convert the strain of the beam into seedling emergence force. This dataset has been used in research work titled 'Greater emergence force and hypocotyl cross sectional area may improve wheat seedling emergence in sodic conditions' (Anzooman et al., 2018) [1].