Growth parameters and economics of rice varieties under aged seedling transplantation in north coastal Andhra Pradesh

Introduction

India must increase its annual grain output to 120 million tons by 2025 from the current 108.32 million tons to sustainably feed its rapidly growing population of 1.5 billion people (Ministry of Agriculture and Farmers Welfare, 2022-23) [10] . Rice (Oryza sativa L.) is predominantly a kharif season crop and is the most important food crop cultivated across India, contributing to over 40 per cent of total food grain production. Although, India ranked 1 st in area and 2 nd in production but struggling to have notable productivity among rice-growing countries. Rice is one of the most important food crops in the North coastal Andhra Pradesh (Srikakulam, Vizianagaram and Vishakhapatnam), with 3.20 lakh hectares of the actual area mostly sown during kharif (Directorate of Economics and Statistics, A.P, 2023) [11] with an average production of 3850 kg ha -1 per year, which is conspicuously lesser crop productivity compared to both state and national level. Planting of kharif rice crop closely follows the onset of southwest monsoon in June/July and its subsequent progress through September to augment the water requirement at critical crop growth stages. Optimum window for nursery sowing and transplanting is critical for achieving higher grain yield. Rice grown after optimum planting window usually suffers from slow growth and poor crop stand and is prone to pests and diseases. Sah et al. (2023) [6] also reported that seeding age at transplanting is one of the most important factors that substantially regulate potential agronomic traits, i.e. tillering, panicle number and grain yield per unit of the land area. In North-Coastal Andhra Pradesh, most of the rice-growing area is under uncertain irrigation systems. Whenever monsoon is delayed, farmers are compelled to transplant rice late in the season with over-aged seedlings due to late release of canal water. Delayed transplanting usually extends the growth of seedlings in seedbed and shortens their growth period in main field which results in reduction in yield. Therefore, under such unavoidable circumstances, farmers are to be insured against yield loss by identifying rice varieties which can produce satisfactory yield even when transplanted overage seedlings. Hence, it is felt pertinent to evaluate recently released high-yielding rice varieties for their suitability under delayed transplanting conditions with over-age seedlings in the north coastal districts of Andhra Pradesh.

Materials and Methods

A field experiment was conducted on sandy loam soil at the college farm of Agricultural College, Naira, Srikakulam to study the yield and yield attributes of old aged seedlings as influenced by different varieties in a split-plot design, comprised of three age of seedlings (30, 45 and 60 days old) assigned to main Plots and eight varieties (V 1: MTU-7029, V 2: BPT-5204, V 3: MTU-1061, V 4: MTU-1121, V 5 :MTU-1223, V 6 :MTU-1224, V 7 :MTU-1262 and V 8 :RGL-2537) were assigned to sub plots. All the recommended packages of practices were followed to raise a good crop. Nursery field was thoroughly puddled and well levelled. The entire field area was demarcated into 24 plots each of size 3 m² (3 m×1 m) and individual plots were separated by bunds for 3 different aged seedlings of 30, 45 and 60 days respectively. The seed of eight varieties under investigation i.e., MTU 7029, BPT 5204, MTU-1061, MTU-1121, MTU-1223, MTU-1224, MTU-1262 and RGL-2537 were soaked in water for 24 hours, drained and incubated in moist gunny bags for 36 hours. The sprouted seeds were broadcasted uniformly over the well-prepared seedbeds. A fertilizer dose of 1.5: 0.5: 0.5 kg N, P 2 O 5 and K 2 O per 100 m -2 was applied as basal dose. The seedlings were uprooted according to the treatments and transplanted in the main field. The plots were irrigated with a 2.5 cm depth of water and irrigated again on the appearance of hair line cracks on the soil surface. This practice was continued till the flowering stage of the crop. Nitrogen as Urea was applied in two splits i.e., 70% at the time of transplanting, and 30% at an active tillering stage in the subplots as N @ 150 kg ha -1 and N @ 120 kg ha -1. As per the treatments in the subplot, the entire quantity of phosphorus as a Single Super Phosphate was applied at the time of final puddling and potassium was applied in two splits, 50% at the time of transplanting and the remaining 50% at panicle initiation.The split pot design, developed by Fisher (1925) [12] was used to compile and analyse the collected data, consisting of both pre and post-harvest observations. Critical differences were determined for those parameters that were found to be statistically significant (p<0.05) to compare the impact of the various treatments.

Results and Discussion

Plant height (cm) Data pertaining to plant height of rice sampled at three stages viz., Active tillering, Panicle initiation and harvest are presented in table 1. Perusal of the data revealed that age of seedlings at the time of transplanting as well as varieties were found to exert a progressive and significant influence on plant height of rice at all the three stages of sampling. However, the interaction affect between the age of nursery and varieties was found to be absent. As regards plant height of rice, age of seedlings was found to influence this parameter to a statistically detectable magnitude at all the three stages viz., Active tillering, Panicle initiation and harvest. Throughout the crop growth, the tallest plants were noticed when rice seedlings transplanted at 30 days age which was however, found parity with 45 days old seedlings. Significantly shorter plants were noticed with 60 days old seedlings which was however on par with 45 days old seedlings at Active tillering. Significantly taller plants observed at all the three stages of sampling in plots which were transplanted with the youngest seedlings and the plant height was decreased with increase in age of seedlings at transplanting, might be due to the fact that the younger seedlings with large meristimatic tissue activity resulting in greater mitosis to contribute to stem elongation. Further, higher phyllocrone production in younger seedlings together with less pulling shock due to confinement of fibrous root system to shallow depths compared to old aged seedlings also might have contributed to greater plant height. Sah et al. (2023) [6] and Singh et al. (2023) [3,4] also expressed similar views with respect to recording greater plant height in younger seedlings compared to aged ones With regards to the influence of varieties on plant height of rice, marked differences were observed among the rice varieties tested at all the three stages viz., Active tillering, Panicle initiation and harvest. Throughout the crop growth, the plant height was found to be the highest with RGL-2537 which was however showed statistically parity with MTU-1061. The shortest stature was noticed in MTU-7029 which was however, comparable with MTU-1224. Statistically detectable disparities in plant height noticed among the varieties tried could be attributed to the genetic makeup of the individual cultivar, resultant of parentage. These findings are in corroboration with those reported by Nawaz and Khan (2023) [13] . [3,4] [13] also reported similar results The data pertaining to total number of tillers m -2 recorded at Active tillering, Panicle initiation and Flowering are presented in table 3. Perusal of the data revealed that there was a gradual increase in total number of tillers m -2 from active tillering to panicle initiation stage and a slight decrease at flowering due to age of nursery at transplanting as well as different varieties tried. Total number of tillers m -2 in rice recorded at Active tillering, Panicle initiation and Flowering stages was found to be significantly influenced by age of nursery at transplanting. Maximum number of total tillers m -2 was registered when seedlings were transplanted at 30 days age(A 1 ), while it was the lowest with 60 days old seedlings (A 3 ). Perceptible decline in total number of tillers m -2 observed with advancement of age of nursery from 30 days across 45 to 60 days could be attributed to the fact that the younger nursery established in the main filed at tender age (A 1 ) passed through favourable growing environment for comparatively long period over successive advance aged nursery (A 2 & A 3 )which might have enabled to put forth large number of tiller per clump and in turn more number of total tillers m -2 .While, in the case of older nursery, significant drop in tiller production might be due to the reason that when seedlings are allowed to stay for longer period of time (A 2 and A 3 ) in the nursery beds, the chances of primary tiller buds on the lower nodes of the main culm got degenerated increases, leading to reduced tiller production, in addition to greater pulling shock endured by aged seedlings. Similar findings were also reported by Singh et al. (2023) [3,4] . With regard to the influence of varieties on total tillers m -2 of rice at Active tillering, marked differences were observed among the rice varieties tested. Total tillers m -2 was found to be the highest in MTU-1223 (V 5 ) which shows statistical parity with V 8 (RGL-2537), while significantly lower number of total tillers m -2 was observed in BPT-5204 (V 2 ) followed by MTU-1061 (V 3 ). As regards the interaction effect between age of nursery at transplanting and varieties tried, significantly large number of tillers m -2 was noticed with MTU-1262 (V 7 ) when 30 days old seedlings (A 1 ) were transplanted which was however, found statistical parity with MTU-1223 (V 5 ) at the same age of nursery. Significantly lesser number of total tillers m -2 were observed in MTU-1121 (V 4 ) when nursery of 60 days old was transplanted which was however, statistically comparable with MTU-1262 (V 7 ) at the same age nursery. (Table 3). Total number of tillers counted at panicle initiation stage of rice was found to be significantly altered by age of nursery at transplanting as well as varieties. The interaction effect between these two parameters was also found be statistically detectable (Table. 4). With regard to total number of tillers m -2 as influenced by different varieties, V 5 (MTU-1223) produced significantly more number and exhibited its supremacy over other varieties. Number of tillers m -2 was observed to be minimum in V 2 (BPT-5204), which was however, comparable with V 4 (MTU-1121).

With regard to interaction effect, variety MTU-1262 (V 7 ) when transplanted with youngest nursery (A 1 ) produced the highest total number of tillers m -2 and found significantly superior to any other treatment combinations. While, variety MTU-1121 (V 4 ) transplanted with the oldest nursery (A 3 ) recorded significantly lower tiller production which was however, comparable with MTU-1262 (V 7 ) at the same age of nursery (A 3 ). At flowering stage, regarding varieties, MTU-1223 (V 5 ) showed its supremacy by producing the highest number of tillers m -2 compared to all other varieties tried. Total tillers m -2 were found to be significantly lower in BPT-5204 (V 2 ) which was however, found statistical parity with MTU-1121 (V 4 ).Regarding interaction effect, significantly large number of total tillers m -2 were registered with MTU-1262 (V 7 ) planted with the youngest seedlings (A 1 ) which were however statistically on par with MTU-1223 (V 5 ) at the same age of nursery (A 1 ). Total tillers m -2 of rice were observed to be minimum in MTU-1121 (V 4 ) when established with aged seedlings (A 3 ) which was however comparable with MTU-1262 (V 7 ). Among different varieties tried, significantly large number of total tillers m -2 were found to associate with MTU-1223 at all the three intervals of sampling and this could be attributed to the varietal character which is largely governed by the genetic constitution of the cultivar. Statistically quantifiable superiority of MTU-1223 in producing total tillers m -2 when transplanted with 30 days old seedlings (A 1 ) might be due to synergestic interaction between innate potential of the cultivar and the extended favourable growing environment in which the crop spend the tillering phase. These results are corroborating the findings of Sah et al. (2023) [6] .

The data pertaining to drymatter production of rice recorded at Active tillering, Flowering and Harvest are presented in table 4. Perusal of the data revealed that there was a gradual increase in drymatter production (kg ha -1 ) from active tillering to harvest stage due to age of nursery at transplanting as well as different varieties tried. At active tillering stage, drymatter production (kg ha -1 ) of rice altered to a statistically perceptible level due to differences in age of nursery at transplanting. Significantly higher drymatter production was noticed at Active tillering, Flowering and Harvest when 30 days old (A 1 ) rice seedlings were transplanted, while it was gradually decresed with increase in age of seedlings at transplanting recorded the lowest with 60 days old seedlings (A 3 ).With regard to interaction effect between these factors on drymatter accumulation, it was not statistically noticeable at Active tillering whereas The interaction effect between these two parameters was also found be statistically detectable at flowering and at harvest stages. Drymatter production is the result of plant height and number of tillers per clump of rice. In the present field trial, rice nursery transplanted at 30 days age registered significantly taller plants and more number of tillers m -2 . Transplanting nursery at comparatively lesser age creates an opportunity for the seedlings to harness edaphic and climatic resources effectively for a prolonged period to accumulate more drymtter compared to older seedlings as the growing conditions enable the younger seedlings to access adequate growth resources under fairly accommodative situation in the main field than the preceding life they spend in the nursery bed under sheer competition for essential growth resources confirmed in lines by research findings of Singh et al. (2023) [3,4] . Drymatter production (kg ha -1 ) at Active tillering exerted statistically measurable influence on the drymatter accumulation of rice by different varieties (Table . 5 and6). Drymatter production (kg ha -1 ) was found to be the highest with V 5 (MTU-1223) which was however, found on par with V 1 (MTU-7029), and V 7 (MTU-1262). Drymatter production (kg ha -1 ) was the lowest in V 2 (BPT-5204) which was however, comparable with V 4 (MTU-1121), V 3 (MTU-1061), and V 6 (MTU-1224).

Drymatter production (kg ha -1 ) at flowering stage exerted statistically measurable influence on the drymatter accumulation of rice due to different varieties. Drymatter production (kg ha -1 ) was found to be the highest with V 5 (MTU-1223) which was however, found on par with V 1 (MTU-7029), V7 (MTU-1262) and V 8 (RGL-2537). Drymatter production (kg ha -1 ) was the lowest in V 3 (MTU-1061) which was however, comparable with V 6 (MTU-1224),V 4 (MTU-1121) and V 2 (BPT-5204).With regard to interaction effect, MTU-1262 (V 7 ) when transplanted with youngest nursery (A 1 ) produced the highest drymatter production (kg ha -1 ) which was however statistically on par with MTU-1223 (V 5 ), and RGL-2537 (V 8 ). While, MTU-1224 (V 6 ) transplanted with the oldest nursery (A 3 ) recorded significantly lower drymatter production (kg ha -1 ) which was however, comparable with MTU-1262 (V 7 ), MTU-1061(V 3 ), MTU-1121 (V 4 ) and MTU-1224 (V 6 ) at the same age of nursery (A 3 ). At Harvest, drymatter production (kg ha -1 ) with regard to varieties, MTU-1223 (V 5 ) registered maximum drymattter production which was however, comparable with MTU-1262 (V 7 ) and RGL-2537 (V 8 ). Drymatter production (kg ha -1 ) was observed to be significantly lower in MTU-1121 (V 4 ) which was however, found statistical parity with and BPT-5204 (V 2 ). Differences in drymatter production (kg ha -1 ) of rice at harvest were found to be altered significantly due to interaction between age of seedlings at transplanting and various varieties tried (Table. 6). Significantly higher drymatter production (kg ha -1 ) was registered with MTU-1262 (V 7 ) planted with the youngest seedlings (A 1 ) which was however, statistically on par with MTU-1223 (V 5 ) at the same age of nursery (A 1 ). Dry matter production (kg ha -1 ) of rice at harvest was observed to be the lowest in MTU-1224 (V 4 ) when established with aged seedlings (A 3 ) which was however, comparable with MTU-1224 (V 6 ). Significantly higher drymatter production observed with MTU-7029 (V 1 ), MTU-1223 (V 5 ), MTU-1262 (V 7 ) and RGL-2537 (V 8 ) could be attributed to the fact that these verities produced taller plants coupled with greater tillering ability over rest of the varieties tried. Further, with regard to interaction effect between aged of rice seedlings at transplanting and varieties which was found significant in the present investigation, voluminous literature is available in support of these findings since the genetic potential of the variety is best expressed under the most favourable growing environment, which was encountered by the seedlings of younger age. Similar results of higher drymatter production with younger seedlings were also reported by Oni et al. (2023) [14] .

Days to 50% flowering and maturity

Data pertaining to days required to attain 50% flowering and maturity of rice as influence by age of nursery at transplanting as well as verities are presented in table 6. Scrutiny of the data revealed that transplanting of rice with different ages and their interaction with varieties did not alter either days to reach 50% flowering or maturity of rice to a statistically perceptible magnitude. However, both these parameters were found to influence significantly due to different varieties tried. [6] .

Economics

Perceptible differences were observed regard to gross, net returns and B:C ratio (Table 7) due to age of nursery at transplanting as well as varieties of rice tried. Among seedlings of different ages tried, rice crop established by transplanting with 30 days old seedlings (A 1 ) exhibited its superiority in producing higher gross returns, which was higher by Rs 10715/-compared to 45 days old seedlings (A 2 ) and Rs 36329/-over planting of 60 days old seedlings (A 3 ). Similarly higher net returns also realized by planting 30 days old seedlings (A 1 ) which was higher by Rs 11564/-compared to 45 days old seedlings (A 2 ) and Rs 38828/-over planting of 60 days old seedlings (A 3 ). B:C ratio also maximum with 30 days old seedlings (A 1 ) and gradually declined with increasing age of seedlings at the time of transplanting. Higher grain yield couple with less cost of production in the crop transplanted with 30 day seedlings might have resulted in higher profits compared to 45 and 60 days aged seedlings. Singh et al. (2023) [3,4] also reported similar results earlier.

With regards to influence of varieties on gross returns, net returns of rice and return per rupee invested on rice marked differences were observed among the varieties tried. The Higher gross returns, net returns of rice and return per rupee invested on rice were noticed with MTU-1223 (V 5 ) followed by RGL-2537 (V 8 ) and MTU-1224(V 6 ).The lowest gross returns, net returns of rice and return per rupee invested on rice were associated with MTU-1121 (V 4 ) followed by BPT-5204 (V 2 ). Profit of Rs 17190/-was the difference between the maximum and minimum among the varieties. The yield difference and difference in cost of production among the varieties might be the reason for difference in returns. Similar results were reported earlier by Mohapatra et al. (2021) [15] . As regards the interaction effect between age of nursery at transplanting and varieties tried, maximum gross returns and net returns were noticed with MTU-1262 (V 7 ) when 30 days old seedlings (A 1 ) followed by MTU-1061 (V 3 ) MTU-1223 (V 5 ), MTU-1224 (V 6 ) and MTU-7029 (V 1 ) at the same age of nursery. The gross returns and net returns were minimum with MTU-1121 (V 4 ) when nursery of 60 days old was transplanted.

Conclusion

Among the three age of seedlings for transplanting, planting of 30 days seedlings proved superior by recording higher growth parameters like plant height, leaf area index, total no of tillers, dry matter production and days to flowering & maturity, gross returns, net returns and return per rupee invested on rice compared to planting of 45 days and 60 days old seedlings. Decrease in net returns by Rs 11564/-and 38828/-respectively due to planting 45 days and 60 days compared 30 days old seedlings Among the Varieties tested, the higher plant height was found with RGL-2537, Leaf area index was found with MTU-7029, whereas total tillers m -2, and drymatter production (kg ha -1 ), gross returns, net returns of rice and return per rupee invested on rice was found to be the highest in MTU-1223 (V 5 ). Further the study can be concluded as decline in returns are certain with increasing age of seedlings in rice over 30 days, however the profit loss can be minimized noticeably by choosing varieties Viz., MTU-1223, MTU-1224, MTU-1262 and MTU-1061when 45 days old seedlings. transplanted and RGL-2537. and MTU-1223. when 60 days old seedlings.

References

1. Akter M, Paul NC, Sarkar SK, Mahapatra CK, Sarkar MAR, Paul SK. Growth analysis of short duration transplanted Aus rice (cv. Parija) under three agronomic practices. Arch Agric Environ Sci. 2022;7(1):51-60.
2. Ju C, Zhu Y, Liu T, Sun C. The effect of nitrogen reduction at different stages on grain yield and nitrogen use efficiency for nitrogen efficient rice varieties. Agronomy. 2021;11(3):462.
3. Singh A, Dev AN, Singh AK, Singh R, Singh A, Pandey AK. Impact of different age of seedlings and double transplanting on growth and yield of rice under rainfed condition. J Agric Sci. 2023;12(6):4821-4826.
4. Singh NK, Narang MK, Thakur SS, Singh M, Singh SK, Prakash A. Influence of transplanting techniques and age of wash root type seedlings on planting attributes of paddy rice. Cogent Food Agric. 2023;9(1)2193451.
5. Vishwakarma A, Singh JK, Sen A, Bohra JS, Singh S. Effect of transplanting date and age of seedlings on growth, yield and quality of hybrids under system of rice intensification and their effect on soil fertility. Indian J Agric Sci. 2016;86(5):679-685.
6. Sah MK, Shrestha A, Shah P, Mishra A. Impact of age of seeding and varieties on yield and yield attributing characters of rice in central Terai region of Nepal. Agron J Nepal. 2023;7:88-93.
7. USDA Agricultural Marketing Service, Farm Service Agency. World Agricultural Supply and Demand Estimates, 9 November 2023. Available from: https://www.usda.gov/oce/commodity/wasde/wasde1123.
8. Jahan A, Islam A, Sarkar MIU, Iqbal M, Ahmed MN, Islam MR. Nitrogen response of two high yielding rice varieties as influenced by nitrogen levels and growing seasons. Geol Ecol Landscapes. 2022;6(1):24-31.
9. Directorate of Economics and Statistics. Agricultural Statistics at a Glance 2020-21 Andhra Pradesh. 15th September 2021. Available from: https://des.ap.gov.in/jsp/social/ASAG2020-21. [Accessed 2021 Sep 15].
10. Ministry of Agriculture and Farmers Welfare. Second Advance Estimates of Production of Food Grains for; c2022-2023, Feb. Available from: [URL].
11. Directorate of Economics and Statistics, A.P. Monthly Season and Crop Conditions Report for the Month of; c2023 Aug. Available from: https://des.ap.gov.in/jsp/social/Monthly_Season_Crop_Con dition_Report_Aug_2023. [Accessed 2023 Aug].
12. Fisher RA. Theory of statistical estimation. Math Proc Camb Philos Soc. 1925;22(5):700-725.
13. Nawaz MA, Khan D, Khan QM. Role of Artificial Intelligences in Shaping Customer Demand in E-commerce: A Case Study of Pakistan. Annals of Human and Social Sciences. 2023 Dec 29;4(4):626-635.
14. Oni OE, Longe OM. Analysis of secondary controller on MTDC link with solar PV integration for inter-area power oscillation damping. Energies. 2023 Aug 29;16(17):6295.
15. Mohapatra S, Menon NG, Mohapatra G, Pisharody L, Pattnaik A, Menon NG, et al. The novel SARS-CoV-2 pandemic: possible environmental transmission, detection, persistence and fate during wastewater and water treatment. Science of the Total Environment. 2021 Apr 15;765:142746.