Sowing date and other factors that impact on pod-set and yield in chickpea

Transcription

1 Sowing date and other factors that impact on pod-set and yield in chickpea Key words chickpea, sowing date, row spacing GRDC code CSA00013 Take home message Jeremy Whish and Brett Cocks, CSIRO Ecosystem Sciences, 203 Tor St Toowoomba 4350 Plant chickpeas on a date so they flower when the mean daily temperature is greater than 15 C. When planting later than the 15 th June consider reducing the row spacing and increasing plant density. Short season varieties may have a role in the future, but without disease resistance are too risky. Introduction In the decade between 1999 and 2009 the popularity and success of chickpea production in the northern grain region increased. Much of this success has come as a result of new varieties with increased plant height reducing harvest losses and improved disease resistance. Agronomically, recognition of the importance of stored soil water has improved the reliability of yields. The main chickpea varieties grown in the northern grains region of eastern Australia are long-day phenological types (Berger et al. 2004) and as such are suited to late autumn or early winter sowing. A sowing window between 10 May and 20 July was identified as optimal for chickpea crops grown in southern Queensland and northern NSW (Brinsmead 1992). Horn et al. (1996) confirmed the work of Brinsmead (1992) but recommended early May to mid June as the optimum sowing times. Regan s (2006) work not only explored the influence of sowing date on yield through avoidance of cool temperatures, but also as a strategy to reduce the impact of disease. The expansion of chickpea from eastern to western parts of the region has caused a re-thinking of when to plant, however the key message still remains, the optimal time to sow chickpea depends on the interaction between the environment and the available germplasm (Whish, 2007). Unfortunately climatic variability or operational logistics of the farm means planting crops at the optimal time is not always feasible. Within the northern cropping zone a genetic alternative, a short season variety, does not exist at this time. Changing the row configuration and ensuring plant densities are adequate is an alternative way to maintain yield with existing plant material. Despite recent experiences, the key to sowing chickpeas in the northern grains region is understanding the environment. When to sow Chickpea genotypes have excellent frost tolerance at ambient temperatures > -8 C when in a vegetative state; however, when in a reproductive state they are sensitive to cool temperatures. Flower abortion will occur at mean minimum temperatures of less than 15 C (Siddique and Sedgley 1986, Berger et al. 2004, Clarke et al. 2004, Whish 2007).

2 The progress to flowering in chickpea is significantly influenced by temperature and can be described by the accumulation of thermal time {(max T - mint )/2 assuming a base temperature of 0} (Roberts et al. 1985). When sufficient heat units have been accumulated the plant will enter a reproductive phase and start flowering. It is at this point that chickpea tolerance of stress is significantly reduced; temperatures below 15 C can cause flower abortion, sub-zero temperatures can cause flower, pod and seed abortion, and severe frost can cause total defoliation and death (Loss et al. 1998, Clark and Siddique 2004). Temperatures greater than 35 C can also cause flower loss and water stress. Flowering chickpeas are also sensitive to water logging with a similar response to low temperatures with flower and pod abortion and leaf senescence (Cowie et al., 1996). Knowledge of the phenology of a chickpea variety combined with the local environment will help identify the best time to plant. In the Accredited Chickpea Manual, APSIM and local meteorological files were used to give an estimate of the best time to plant chickpea in different regions: Figure 1 shows results for Goondiwindi.

3 Figure 1. Date of flowering for Jimbour Chickpeas in relation to mean daily temperature, each figure represents a different specific sowing date. If avoiding cold temperatures is the only criterion then the later the crop is planted the better. However, chickpeas also suffer from a degree of high temperature stress and the later the crop is planted the lower the yield potential due to the shorter season. Determining the best time to plant is a tradeoff between losing some yield at the beginning of flowering and some at the end. Considering whole farm management is the simplest approach, plant paddocks high on slopes earlier and low hollow paddocks later. An examination of 42 commercial paddocks between 2003 and 2004 of Jimbour chickpeas planted between the 15 th of May and 15 th of June found on average the first 3 fruiting sites and the last 4 fruiting sites along a chickpea s main stem are aborted as a result of cool temperatures and terminal drought. This loss equates to a 50 % loss of potential fruiting sites. More recently chickpeas planted after the 15 th of May at Billa Billa 2008 lost 3 to 4 fruiting sites at the end of the season, but only a single flower due to cold at the start of flowering. These results were consistent, irrespective of variety (Jimbour, Hatrick, Kyabra, Moti, Sonali). In the more western areas warm temperatures and early-planted crops can create a large canopy with few flowers. Planting later is one way to reduce this excessive early growth and spare water for filling grain; however, the ideal is to time flowering to coincide with the date when mean daily temperatures exceed 15 C. This provides the longest opportunity for flowers to develop into pods and grain. Planting later The later a crop is planted the shorter the potential season for growth and development, especially if the season has a hot dry spring. When this occurs plants have less time to develop canopies and roots

4 which can result in only partial use of soil water resources and a below potential yield. Reducing the row spacing of late planted crops and ensuring an adequate plant density is one method to help late planted crops access all available soil water. Unfortunately inconsistent results have been achieved in trying to demonstrate the benefits of this method. In 2008 across three sites no difference in yield was observed between wide and narrow spaced crops. However, in 2009 late planted narrow (30cm) rowed crops significantly out yielded wide rowed crops (60cm and 100 cm). This single season supported the trend observed in 2003 where narrow planted late crops produced higher yields. From 8 trial years of data the narrow rows have never yielded less than the wide rows when planted late. Would short season varieties help? There is currently no short season cultivars recommended for use in the northern grains region. Pulse Breeding Australia has a breeding objective of incorporating disease resistance into existing short phenology material. The option of a short season chickpea cultivar would provide an alternative for lateplanted chickpeas. However, trials run in 2008 and 2009 that included the short season varieties Moti and Sonali showed no yield difference when compared to recommended northern varieties (Figure 2). The key Figure 2. Comparison of yields for five different chickpea varieties* showing no significant difference between the short phenology chickpeas Moti and Sonali and existing long season varieties. * Hatrick, Jimbour, Kyabra and Moti are protected under the Plant Breeders Rights Act 1994.

5 The key to planting chickpea in the northern grains region is to be mindful that the crop is susceptible to stress during flowering. Selecting a planting date that will limit this stress is a practical way to give the crop the best chance of achieving its potential yield. References Berger JD, Turner NC, Siddique KHM, Knights EJ, Brinsmead RB, Mock I, Edmondson C, Khan TN (2004) Genotype by environment studies across Australia reveal the importance of phenology for chickpea (Cicer arietinum L.) improvement. Australian Journal of Agricultural Research 55, Brinsmead, R.B. (1992) Chickpeas by cultivar by planting time studies in Queensland. In Proceedings 6th Australian Society of Agronomy Conference. Armidale NSW. (The Australian Society of Agronomy). (access April 2006) Clarke HJ, Siddique KHM (2004) Response of chickpea genotypes to low temperature stress during reproductive development. Field Crops Research 90, Cowie, A.; Jessop, R. S.; MacLeod, D. A. (1996). A study of waterlogging damage in Australian chickpea cultivars. Plant and soil Horn CP, Birch CJ, Dalal RC, Doughton JA (1996) Sowing time and tillage practice affect chickpea yield and nitrogen fixation. 1. Dry matter accumulation and grain yield. Australian Journal of Experimental Agriculture 36, Knights, E. (1991) Chickpea. In New Crops: Agronomy and potential of Alternative Crop Species. (eds RS Jessop, RL Wright) pp Inkata Press, Melbourne. Regan KL, Siddique KHM, Brandon NJ, Seymour M, Loss SP (2006) Response of chickpea (Cicer arietinum L.) varieties to time of sowing in Mediterranean-type environments of south-western Australia. Australian Journal of Experimental Agriculture 46, Siddique KHM, Sedgley RH (1986) Chickpea (Cicer arietinum L.) a potential grain legume for southwestern Australia: Seasonal growth and yield. Australian Journal of Agricultural Research 37, Whish JPM, Castor P, Carberry PS (2007) Managing production constraints to the reliability of chickpea (Cicer arietinum L.) within marginal areas of the northern grains region of Australian Journal of Agricultural Research, 58, Contact details Jeremy Whish CSIRO Ecosytem Sciences Ph: Jeremy.Whish@CSIRO.au Varieties displaying this symbol beside them are protected under the Plant Breeders Rights Act 1994.