Seed protectant-mediated retention of physiological quality and seedling vigour in chickpea (Cicer arietinum L.) during storage

Introduction

Chickpea (Cicer arietinum L.) is an important food legume valued for its nutritional contribution and adaptability to relatively dry production environments. Preservation of seed physiological quality after harvest is essential because storage-induced deterioration progressively reduces germination, seedling growth and crop-establishment potential. Temperature, relative humidity, seed moisture and duration of storage influence the rate of deterioration. In addition to physiological ageing, stored chickpea is vulnerable to the pulse beetle, Callosobruchus chinensis whose feeding activity can damage cotyledonary tissues and reduce seed viability and vigour. Seed deterioration is a progressive process in which loss of vigour precedes complete loss of viability. Consequently, seed germination alone may not adequately describe the physiological status of a stored seed lot; root and shoot growth, seedling dry matter and vigour indices provide complementary information on the capacity of aged seeds to produce vigorous seedlings. Further emphasizes that seed ageing is associated with membrane deterioration, altered metabolism, impaired reserve mobilization and oxidative stress which ultimately affect germination and seedling development. Botanical oils offer an alternative or complementary approach to synthetic protectants because plant-derived materials may possess insecticidal, repellent and antifeedant properties. Chemical seed protectants can provide more predictable protection against storage pests, but their use should be judicious. Therefore, the present study compared selected botanical and chemical seed treatments for their ability to preserve physiological seed quality of chickpea during nine months of storage with emphasis on germination, seedling growth, dry matter and vigour indices.

Materials and Methods

The laboratory study was conducted during 2025-26 at the Seed Technology Research Unit (STRU), Dr. PDKV, Akola, Maharashtra using chickpea (Cicer arietinum L.) variety PDKV Kanak. The seed lot was manually cleaned and subjected to the respective seed treatments prior to storage. The experiment comprised eleven treatments including an untreated control (T0), five botanical oils viz., castor oil @ 5 ml kg⁻¹ seed (T1), mustard oil @ 5 ml kg⁻¹ seed (T2), neem oil @ 5 ml kg⁻¹ seed (T3), sesame oil @ 5 ml kg⁻¹ seed (T4) and karanj oil @ 5 ml kg⁻¹ seed (T5), and five chemical insecticides viz., emamectin benzoate @ 40 mg kg⁻¹ seed (T6), spinetoram 11.7 SC @ 8.5 mg kg⁻¹ seed (T7), Sivanto 17.09% SL @ 0.01 ml kg⁻¹ seed (T8), deltamethrin (Decis) 2.8% EC @ 0.04 ml kg⁻¹ seed (T9) and dinotefuran 20 SG @ 10 mg kg⁻¹ seed (T10). The treated seed was maintained under ambient storage conditions for 270 days in a Completely Randomized Design (CRD) with three replications. Representative seed samples were withdrawn at 0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days after storage (DAS) for assessment of physiological seed quality. Standard germination testing was employed to determine germination percentage. On the eighth day of the germination test, ten normal seedlings were randomly selected from each replication for measurement of root and shoot length. Root length was measured from the point of attachment of the seed to the tip of the primary root, whereas shoot length was measured from the point of attachment to the shoot tip and the observations were expressed in centimetres. For determination of seedling dry weight, the same normal seedlings used for root and shoot measurements were dried in a hot-air oven at 103 ± 2°C for 17 ± 1 h, cooled and weighed with the mean values expressed in milligrams. Seedling vigour index-I was computed as the product of germination percentage and total seedling length where total seedling length represented the combined root and shoot length. Seedling vigour index-II was calculated as the product of germination percentage and seedling dry weight. Thus, the physiological response of treated chickpea seed during storage was evaluated through seed germination, root length, shoot length, seedling dry weight and vigour indices-I and II.

Results and Discussion

Seed germination exhibited a progressive decline with increasing storage duration across all treatments indicating gradual deterioration of seed viability during ageing. Treatment differences remained statistically non-significant up to 60 DAS but became significant from 90 DAS onwards. At 270 DAS, seed germination ranged from 70.25 to 81.75 per cent. The highest germination was recorded with emamectin benzoate @ 40 mg kg⁻¹ seed (T6) and dinotefuran 20 SG @ 10 mg kg⁻¹ seed (T10), each recording 81.75 per cent followed by spinetoram 11.7 SC @ 8.5 mg kg⁻¹ seed (T7) with 81.25 per cent. Among the botanical treatments, neem oil @ 5 ml kg⁻¹ seed (T3) retained the highest germination (77.50%), followed by castor oil (T1) at 77.00 per cent. While, the untreated control declined from 95.50 per cent at 0 DAS to 70.25 per cent at 270 DAS. The comparatively greater retention of germination in treated seed lots indicates delayed deterioration and better preservation of seed viability during storage. Root length progressively decreased with advancement of storage duration, with treatment differences remaining nonsignificant up to 90 DAS and becoming significant from 120 DAS onwards. Emamectin benzoate (T6) consistently maintained the highest root length declining from 15.00 cm at 0 DAS to 11.00 cm at 270 DAS followed by spinetoram (T7) at 10.88 cm. Among botanicals, neem oil (T3) recorded the highest root length of 10.50 cm at 270 DAS, whereas the untreated control exhibited the greatest decline from 12.38 cm to 7.25 cm. Shoot length also showed a progressive reduction during storage with significant treatment differences appearing from 120 DAS. At 270 DAS, dinotefuran (T10) recorded the maximum shoot length (8.63 cm) followed by neem oil (T3) at 8.38 cm, Sivanto (T8) at 8.28 cm and emamectin benzoate (T6) and spinetoram (T7) at 8.25 cm each while the untreated control recorded 6.23 cm. The comparatively greater root and shoot growth retained by treated seed indicates better preservation of physiological competence and post-germination growth potential under prolonged storage. Seedling dry weight declined progressively with storage duration with significant treatment differences emerging from 120 DAS onwards. At 270 DAS, spinetoram (T7) recorded the maximum seedling dry weight (123.25 mg) followed by emamectin benzoate (T6) at 122.50 mg and dinotefuran (T10) and neem oil (T3) each at 118.75 mg. The untreated control showed a marked reduction from 136.00 mg at 0 DAS to 81.25 mg at 270 DAS. Seedling vigour index-I similarly declined progressively as a consequence of reductions in germination and seedling length. At 270 DAS, the highest vigour index-I was recorded with emamectin benzoate (T6) at 1574 followed by spinetoram (T7) at 1554 and dinotefuran (T10) at 1532, while neem oil (T3) was the best botanical treatment with 1463; the untreated control recorded the lowest value (947). Seedling vigour index-II also exhibited a progressive decline with increasing storage duration, reflecting the combined reduction in germination and seedling dry matter accumulation. At 270 DAS, spinetoram (T7) recorded the highest vigour index-II (10015), closely followed by emamectin benzoate (T6) at 10014 and dinotefuran (T10) at 9705. Among the botanical treatments, neem oil (T3) recorded the highest value (9205), whereas the untreated control recorded the minimum (5713). Overall, the results demonstrate that seed protectant treatments predominantly Emamectin benzoate, Spinetoram and Dinotefuran among the chemical treatments and Neem oil among the botanicals were more effective in retaining seed germination, seedling growth, dry matter accumulation and vigour during prolonged storage.

Conclusion

Prolonged ambient storage resulted in progressive deterioration of chickpea seed physiological quality expressed through reductions in seed germination, root length, shoot length, seedling dry weight and vigour indices. The magnitude of deterioration was substantially lower in treated seed than in the untreated control mainly after 120 DAS. Emamectin benzoate @ 40 mg kg⁻¹ seed, Spinetoram 11.7 SC @ 8.5 mg kg⁻¹ seed and Dinotefuran 20 SG @ 10 mg kg⁻¹ seed consistently provided superior preservation of seed physiological quality. Among the botanical treatments, Neem oil @ 5 ml kg⁻¹ seed showed the best retention of seedling growth and vigour during prolonged storage. Overall, the findings demonstrate that suitable pre-storage seed treatment can delay storage-induced deterioration and extend the useful physiological storability of chickpea seed.

Acknowledgement

AcknowledgementThe authors acknowledge the Seed Technology Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola for providing the facilities and support required for conducting the storage and seed-quality evaluations. The authors also acknowledge the concerned research units and laboratories of Dr. PDKV, Akola for their support during the investigation.

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