Physiological responses of chickpea genotypes to terminal drought in a Mediterranean-type environment

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Abstract

Two field experiments were carried out to investigate the effects of terminal drought on chickpea grown under water-limited conditions in the Mediterranean-climatic region of Western Australia. In the first experiment, five desi (small angular seeds) chickpeas and one kabuli (large round seeds) chickpea were grown in the field with and without irrigation after flowering. In the second experiment, two desi and two kabuli cultivars were grown in the field with either irrigation or under a rainout shelter during pod filling. Leaf water potential (Ψl), dry matter partitioning after pod set and yield components were measured in both experiments while growth before pod set, photosynthesis, pod water potential and leaf osmotic adjustment were measured in the first experiment only.

In the first experiment, total dry matter accumulation, water use, both in the pre- and post-podding phases, Ψl and photosynthesis did not vary among genotypes. In the rainfed plants, Ψl decreased below −3 MPa while photosynthesis decreased to about a tenth of its maximum at the start of seed filling. Osmotic adjustment varied significantly among genotypes. Although flowering commenced from about 100 days after sowing (DAS) in both experiments, pod set was delayed until 130–135 DAS in the first experiment, but started at 107 DAS in the second experiment. Water shortage reduced seed yield by 50 to 80%, due to a reduction in seed number and seed size. Apparent redistribution of stem and leaf dry matter during pod filling varied from 0 to 60% among genotypes, and suggests that this characteristic may be important for a high harvest index and seed yield in chickpea.

Introduction

Chickpea (Cicer arietinum L.) is grown across a wide range of environments, from the subtropics of India and north-eastern Australia to Mediterranean-climatic regions around the Mediterranean basin and in southern Australia (Siddique et al., 1999). It has become an important pulse crop in Australia over the past decade. In subtropical areas it is sown after the summer monsoonal rains and grows on stored soil moisture. In Mediterranean-climatic regions it is sown in autumn or spring and grows during the cool wet months of winter and spring. In both environments chickpea crops are exposed to drought during pod set and seed filling (terminal drought). Additionally, the crops can be exposed to low temperatures at flowering that inhibit pod set (Lawlor et al., 1998, Srinivasan et al., 1999) and high temperatures during seed filling that limit yields (Buddenhagen and Richards, 1988). While chickpea is considered one of the most drought-tolerant of the cool season food legumes, the basis of its tolerance is unknown (Singh, 1993).

Methodologies for a better understanding of yield improvement under drought conditions have been reviewed recently (Turner, 1997). Leaf water potential represents an easy measure of water deficit and leaf gas exchange may provide a good ‘sensor’ of the stress. Production of dry matter, early vigour, phenological plasticity and osmotic adjustment have been identified as some of the key characteristics for improved yield and yield maintenance under drought (Turner, 1997). In the present study, these characteristics were studied on six genotypes of chickpea grown on a fine-textured, neutral-to-alkaline soil in the Mediterranean-climatic region of Australia. The genotypes used were a desi (small angular seeds) cultivar, Tyson, a kabuli (large round seeds) cultivar, Kaniva, and four desi advanced breeding lines, which had 14 to 30% higher yields than cv Tyson in 1994, a season with below average rainfall (Siddique, personal communication). The aim of the study was to identify the morphological and physiological characteristics of chickpea that may affect yields in these low rainfall environments. As dry matter redistribution was identified as a key characteristic under terminal drought, this was more intensively studied in a second experiment. In this second study two desi cultivars, Tyson and Sona, and two kabuli cultivars, Kaniva and Bumper, were studied to determine whether there was any variation among genotypes for assimilate redistribution.

Section snippets

Trial design

Six chickpea (Cicer arietinum L.) genotypes, including five desi types: cv. Tyson (121 mg seed−1), acc. ICCV88201 (194 mg seed−1), acc. T1587 (165 mg seed−1), acc. T1069 (182 mg seed−1), and acc. CTS60543 (158 mg seed−1) and one kabuli type: cv. Kaniva (422 mg seed−1) were grown in 1995 on a red brown earth (Calcic Haploxeralf) with a neutral surface pH (6.2 to 6.9) and pH increasing with depth to 8.6 (Thomson et al., 1997) at Merredin (31°30′ S, 118°12′ E), Western Australia. The trial was a randomized

Seasonal conditions

In 1995 at Merredin, daily maximum air temperatures were around 16°C from sowing to 100 DAS, around 19°C for the next 45 days and around 25°C from hereafter until maturity [Fig. 1(A)]. Daily minimum air temperatures below 0°C were observed on five occasions near the onset of flowering [Fig. 1(A)]. Until 153 DAS, daily minimum air temperatures were never above 10°C for more than two consecutive days and then after 153 DAS rose to above 13°C. Daily total solar radiation was around 10 MJ m−2 at sowing

Discussion

One major limitation of chickpea in the cool Mediterranean climate of the south-western Australian cropping zone is its inability to avoid terminal drought by flowering earlier and setting pods at low temperatures. At Merredin, in 1995 we observed some variation among the genotypes in the time to flowering, especially in CTS60543. This putatively cold tolerant line (Lawlor et al., 1998) started flowering one week before Tyson, but did not set pods earlier than the other genotypes. Possibly the

Conclusions

There were no consistent differences in water potential and leaf photosynthesis among the genotypes of chickpea exposed to terminal drought. At Merredin, none of the six genotypes studied were able to avoid drought by early pod development. Although some genotypes flowered earlier than others, all genotypes began pod set at the same time due to the failure of flowers to set pods in the cool spring temperatures. As a consequence, at Merredin, where cold temperatures did not allow early pod set,

Acknowledgements

We thank J.S. Malden, for dry matter sampling and collection of weather data, C.A. Toynes and I.F. LeCoultre, L. Maiolo and L. French, for assistance with the measurements at the field site, and L. Young for the day-to-day running of the experiment. We are grateful to Dr. B.D. Thomson for his helpful advice on the conduct of the experiment at Merredin, Dr. R.J.N. Emery for his help with statistical analyses, and Drs. M. Dracup and S.P. Loss for their useful comments on the manuscript. This

References (24)

  • A.M. Flinn et al.

    Significance of photosynthetic and respiratory exchanges in the carbon economy of the developing pea fruit

    Plant Physiol.

    (1977)
  • H.J. Lawlor et al.

    Improvement of cold tolerance and insect resistance in chickpea (Cicer arietinum L.) and the use of AFLPs for the identification of molecular markers for these traits

    Acta Hort.

    (1998)

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