Pollen fatty acid composition associated with heat tolerance of tropical rice

Charissa Rixon1, Surya Bhattarai1, Ben Ovenden2 and Kerry Walsh1

 1CQUniversity Australia, CQIRP, North Rockhampton QLD 4702, c.rixon@cqu.edu.au
2NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga NSW 2650

Abstract

A nascent rice industry is expanding in Northern Australia. For this industry to be sustainable, it is critical that abiotic stressors are understood and managed. In particular, yield losses due to heat stress causing spikelet sterility will need to be managed through the development of heat tolerant rice varieties. Understanding the physiology of superior heat tolerant genotypes will be important in breeding efforts.  Six selected rice genotypes grown under controlled environment growth cabinets under standard, transient and prolonged heat treatments were evaluated for spikelet sterility and fatty acid composition of the anthers.  Nagina 22, was the only genotype that demonstrated heat tolerance across transient and prolonged heat stress, with low and moderate spikelet sterility, respectively. Other genotypes (Hayayuki, Teqing, Sasanishiki, Lemont and Moroberekan) showed severe spikelet sterility with prolonged heat stress. Nagina 22 also consistently showed significantly higher level of saturated and unsaturated fatty acids levels and concentration of 16 and 18 C fatty acids than the other genotypes. The fatty acid content and the composition of the anther tissue may be linked with heat tolerance, expressed as low spikelet sterility at higher temperature in rice.

Competitive wheats: does more vigour early matter?

Cathrine H Ingvordsen1, David J Smith2, Tina Rathjen1, Gurjet Gill3, Leslie A. Weston4, Washy Gapare1, Greg J Rebetzke1

1 CSIRO, Black Mountain Science and Innovation Park, Canberra, ACT, 2601, http://www.csiro.au/en/Research/AF/Areas/Plant-Science, cathrine.ingvordsen@csiro.au

2 CSIRO, Agriculture and Food, Private Mail Bag, Yanco, NSW, 2703

3 The University of Adelaide, Waite Campus PMB 1, Glen Osmond, SA, 5064

4 Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW, 2678

Abstract

Weeds are an ongoing challenge and herbicide-resistant weeds are on the rise. Incorporating weed-competitive varieties in the non-herbicide integrated weed management toolbox, make up a low cost and low risk approach to decrease the $4.3 billion weed costs Australian growers every year. We have assessed the competitive ability of a diverse set of 100 entries. The 100 entries vary from historic and modern wheat varieties to wheat lines developed to have wide leaves and greater biomass at stem elongation. Among the entries were also durum wheat, triticale and barley. The 100 entries were grown under field conditions in seven environments over three seasons with and without competition from oat or barley used as a weed-surrogate. Through in season measurements and separation of wheat grains and weed-surrogate grains after harvest we identified that wheats with wide leaves and greater biomass at early stem elongation only experienced yield decreases of 4-10% when grown in competition with weed-surrogate, whereas the best varieties decreased yield by 14% and worst decreased yield by 35%. Weed suppression was greatest in the high vigour lines.

Management of early sown wheat: matching genotype to environment

Kenton Porker1, James Hunt2*, Felicity Harris3, Sarah Noack4, Michael Moodie5, Kelly Angel6, Michael Straight7, Genevieve Clarke6, Dylan Bruce8, Ashley Wallace9, Neil Fettell10, Greg Brooke11, Helen McMillan10, Barry Haskins12, Mick Brady5, Todd McDonald5, Brenton Spriggs13, Sue Buderick13, Darcy Warren7.

1 South Australian Research and Development Institute, Hartley Grove, Urrbrae SA 5064

2 Department of Plant, Animal and Soil Sciences, La Trobe University, 5 Ring Rd, Bundoora VIC 3086

3 NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga NSW 2650

4 Hart Field-Site Group, 155 Main North Rd, Clare SA 5453

5 Frontier Farming Systems, 7B Byrne Ct, Mildura VIC 3500

6 BCG, 73 Cumming Ave, Birchip VIC 3483

7 FAR Australia, 4/97-103 Melbourne St, Mulwala NSW 2647

8 South Australian Research and Development Institute, 70 Farrell Flat Rd, Clare SA 5453

9 Agriculture Victoria, 110 Natimuk Rd, Horsham VIC 3400

10 CWFS, 1 Fifield Rd, Condobolin NSW 2877

11 NSW Department of Primary Industries, Trangie Agricultural Research Centre, PMB 19, Trangie NSW 2823

12 AgGrow Agronomy & Research, 7 Francine Ct, Yoogali NSW 2680

13 South Australian Research and Development Institute, McKenzie Rd, Minnipa SA 5654

*Presenting author; j.hunt@latrobe.edu.au

Abstract

Australian wheat breeding programs have responded to the need for cultivars better suited to early sowing and have begun releasing a new generation of winter wheats. However, it is not known which of the new cultivars are best adapted to different environments across the wheat belt, or over what period they can be established and still achieve yields competitive with spring wheats sown in their optimal window. We grew four new winter cultivars and four elite spring checks in experiments with four times of sowing (mid-March, early-April, mid-April, early-May) in 11 different environments across SE Australia during 2017 and 2018. We found that yield of the best winter wheats was comparable with spring wheats sown in their optimal window. Due to the stable flowering time of winter cultivars, adaptation was driven by cultivar flowering time and coincidence with optimal flowering periods in the different environments. The fast winter cultivar Longsword tended to yield best in low yielding (<2.5 t/ha) environments with an early flowering window. The mid-slow winter cultivar DS Bennett yielded most in higher yielding environments (>2.5 t/ha) with a later flowering window, apart from the Mid North of SA where the mid-fast cultivar Illabo was superior. Highest yields of winter wheats were achieved when sown during April and declined when sown in either mid-March or early May.

Effect of sowing date on phenology, plant morphology and yield components in linseed grown in northern NSW in 2015

K A Hertel

NSW Department of Primary Industry

PMB 19, Trangie NSW 2823

  1. kathi.hertel@dpi.nsw.gov.au

Abstract:

Linseed (Linum usitatissium) is a profitable oilseed crop recognised for its role within a rotation for managing cereal crop diseases and pests such as the economically important root lesion nematode species. Consultation with growers and agronomists in northern NSW identified a range of views regarding the ideal sowing window, and a significant knowledge gap of available linseed varieties. A linseed phenology experiment was conducted in 2015 to evaluate the effect of sowing date (SD) on the phenology and yield components of four linseed varieties sown at five SDs (17 April, 8 May, 28 May, 22 June, 13 July). In general, as SD was delayed, the length of key phases such as start of flowering were reduced, plant height and height of lowest capsules decreased and thousand seed weight (TSW) declined. The results show the temperature-driven response of growth and development of four varieties, providing baseline data that could be utilised in crop growth simulations of variable climate scenarios for regional adaptation.

Untangling and unifying adaptive and productivity traits in canola

Harsh Raman1, Rosy Raman1, Yu Qiu1, Brett McVittie1, Simon Diffey2, David Tabah3, and Andrew Easton3,4

 1NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia, https://www.dpi.nsw.gov.au/, harsh.raman@dpi.nsw.gov.au

2National Institute for Applied Statistics Research Australia (NIASRA) University of Wollongong, NSW 2522, Australia

3Advanta Seeds Pty Ltd, Toowoomba, QLD, Australia, 4Present address: Technigro Pty Ltd, Yatala, Queensland, Australia 

Abstract:

Understanding and manipulating the variation for various traits involved in adaptation is essential for sustainable production of canola in diverse environments. We investigated the naturally-occurring variation in flowering time, resistance to blackleg and pod shattering, tolerance to manganese, fractional ground cover, carbon isotope discrimination, water soluble carbohydrate accumulation, and grain yield across diverse growing environments to gain insight of the genetic architecture for these traits. Through extensive phenotyping and genetic analysis, we have untangled genomic regions associated with these traits. We are now developing improved pre-breeding germplasm by combining different genomic regions for stable canola production.

Genetic mapping of flowering time in two interspecific RIL populations of chickpea

Rosy Raman1, Neroli Graham2, Jess Simpson1, Annie Warren2, Sean Bithell2, Dave Wheeler3, Laney Davidson2, Mark Richards1, Kristy Hobson2

1NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia rosy.raman@dpi.nsw.gov.au

2NSW Department of Primary Industries, 4 Marsden Park Rd, Tamworth, NSW 2340, Australia

3NSW Department of Primary Industries, 1447 Forest Road, Orange, NSW 2800, Australia

Abstract

Chickpea (Cicer arietinum) is grown under diverse environments in Australia and often faces various yield limiting abiotic stresses such as low (chilling) temperatures, drought and heat during the reproductive phase. Understanding the genetic control of flowering time, a key adaptive trait is essential for wider adaptation and productivity of chickpea varieties. Currently, our knowledge on the genetic control of flowering time in Australian chickpea varieties is very limited. We utilised two recombinant inbred line (RIL) populations; RB (derived from an early flowering variety, Rupali and late flowering interspecific breeding line (a backcross derivative from Cicer echinospermum), 04067-81-2-1-1) and YB (derived from mid-flowering variety, Yorker and 04067-81-2-1-1). The RB RIL population was evaluated under two sowing times (early and mid-season) at Tamworth and the YB population was evaluated at Wagga Wagga in 2018 to identify genomic regions (quantitative trait loci: QTL) controlling flowering time. One significant QTL was identified on chromosome Ca5 in the RB RIL population and explained up to 16.8% and 11.9% of the phenotypic variation for flowering time in an early and mid-season sowing time, respectively. In the YB RIL population, two significant QTL were identified on chromosomes Ca4 and Ca8 and explained 9.6% and 11.2% of the phenotypic variation. We have also identified that the Australian chickpea varieties Rupali, Sonali and Sona carry the mutated form of the early flowering ELF3 gene on Ca5 (caelf3a). Markers associated with the QTL for early and mid-flowering will accelerate the development of varieties suitable for a wider range of growing environments.

 

 

Management of early sown wheat: Evaluation of G x E x M interactions to increase harvest index and yield of early sown wheat

Kenton Porker1, James Hunt2, Michael Straight3

1 South Australian Research and Development Institute, Hartley Grove, Urrbrae SA 5064 kenton.porker@sa.gov.au

2 Department of Plant, Animal and Soil Sciences, La Trobe University, 5 Ring Rd, Bundoora VIC 3086

3 FAR Australia, 4/97-103 Melbourne St, Mulwala NSW 2647

Abstract:

Early sown slow developing wheats offer increased biomass accumulation, grain number and thus potential grain yield. However, the greater vegetative growth of early sown crops can result in low harvest index (HI).  We evaluated management strategies to improve HI in three early sown winter wheat cultivars using four experiments conducted across south eastern Australia. Strategies included low stand densities (30-50 plants/m²), defoliation, and deferred application of nitrogen fertiliser. We found low stand densities had a small positive effect on HI and grain yield. Defoliation tended to increase HI and but also reduce yield (depending on cultivar) due to reduced biomass which negated much of the increase in HI.  Deferring nitrogen had a variable effect depending on starting soil N and timing of in-season rain to allow crop uptake of top-dressed N.  The management factors studied here have some potential for improvement of HI but responses were variable and with small effect sizes. We conclude that genetic improvement is required to raise HI and yield in early sown wheat.

 

Does root growth slow during fast stem and ear growth in wheat?

Xiaoxi Li1, Michael Weiss1, Richard Richards1

1 CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT 2601, Australia Xiaoxi.Li@csiro.au 

Abstract:

Differential carbon allocation between the shoots and the roots has a potential impact on crop yield as well as water and nutrient use. A pot experiment in 2-m long tubes was established to monitor the shoot and root growth at different stages in wheat until anthesis, and to obtain detailed root distribution data at different soil depths. Two Australian cultivars, Suntop and Westonia, and two Indian cultivars, C306 and HI1500 were compared. After root washing, the seminal roots were sectioned along the root axis into 20-cm segments to measure morphological traits and dry weight. Preliminary results showed that from fully emerged flag leaf to heading, root biomass did not increase while the shoot growth was rapid in all four cultivars. Subsequently, from heading to anthesis, the roots of the two Indian cultivars grew more rapidly than the two Australian ones. The Indian cultivars tended to have smaller root systems than the Australian cultivars. However, the Indian cultivar HI1500 tended to grow more roots at depth (below 1 m) by anthesis, compared with other cultivars. These preliminary results highlight that the carbon allocation to roots declined markedly during the fast stem and ear growth, but variation among cultivars existed in root growth at depth at later growth stages. The study provides information on competition for carbon between roots and shoots which may be useful in modelling. Genetic variation in root growth may be useful for accessing deep soil water during grain-filling and may result in greater yields, especially under terminal drought conditions.

Impact of genotypic variations in transpiration rate on Australian wheat productivity

Behnam Ababaei1, Bangyou Zheng2, Karine Chenu1*

1 The University of Queensland, the Queensland Alliance for Agriculture and Food Innovation (QAAFI), Toowoomba, QLD 4350, Australia, *Email: karine.chenu@uq.edu.au.
2 CSIRO Agriculture and Food, Queensland Biosciences Precinct, St Lucia, QLD 4067, Australia.

Abstract:

Crop water productivity has been receiving special attention in regards to productivity and food security. Limited-transpiration rate (LTR) at high vapour pressure deficit (VPD) has potential to improve drought adaptation. The quantification of the impact of LTR on water consumption, biomass accumulation and yield formation requires the use of dynamic crop modelling to simulate physiological and environmental processes at a suitable time scale and across environments. Here, a new module for the new generation of Agricultural Production Systems sIMulator (APSIM-NextGen) was developed and evaluated, which enables the simulation of atmospheric (VPD) and edaphic water effects on transpiration, biomass production and yield. The module was used to assess the potential of the LTR trait at improving transpiration efficiency at 60 sites across the Australian wheatbelt. Results showed that selection for the LTR trait could result in a 2.5% increase in grain yield nationally through significantly higher transpiration efficiency. Greatest productivity gains were found in eastern part of the wheatbelt where crops rely heavily on stored soil moisture and saving water mid-day (i.e. under high VPD) allows crops to consume it at more critical stages later during the crop cycle.

 

Progress in breeding for Crown Rust (Puccinia coronata f. sp. lolii) resistance in perennial ryegrasses

Chantelle Webb1, Alan Stewart2, Martin Harmer1

1 PGG Wrightson Seeds, 4 Black Swamp Road, Leigh Creek, VIC, 3352, www.pggwrightsonseeds.com.au/Research, CWebb@pgwseeds.com.au,
2 PGG Wrightson Seeds, PO Box 3100 Christchurch 8015

Abstract:

Crown rust (Puccinia coronata f. sp. lolii) is a major disease of perennial ryegrass (Lolium perenne), causing reduced forage yield, plant rooting depth, sward content in mixed pastures, animal intake and digestibility and is associated with animal health problems such as facial eczema. The crown rust resistance (CRR) of contemporary perennial ryegrass cultivars commercially available in Australia has not been studied. Utilising CRR data collected in nine trials over an eight-year period at Ballarat, Victoria, the CRR of 48 commercially marketed varieties were explored. Significant (p<0.001) variation for CRR was identified between marketed perennial ryegrass varieties and the CRR ranking determined for older cultivars and ecotypes was consistent with available literature. Large variation was found in varieties of varying germplasm origins and improvements over older varieties was not large. We suggest progress for this trait may have been temporarily checked by the industries transition to new germplasm sources for other benefits. On average, breeding lines were superior to commercial varieties indicating future improvements are likely. The results of this study suggest that an independent CRR could be easily developed to assist producers choosing between marketed cultivars.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

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David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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