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2 INTRODUCTION Concept of seed physiological maturity (PM)
PM is defined as occuring when the seed reaches its maximum dry weight and vigor (TeKrony et al. 1979). At PM nutrients are no longer flowing into the seed from the mother plant due to the breakdown of vascular bundle connecting seed to mother plant (TeKrony et al. 1979). . Moisture at PM is at certain level depending on crop and cultivar and the moisture totally depend with environment condition after PM (Copeland and MacDonald, 1995). PM permits an accurate measure of the duration of the grain filling period (Crookstton and Hill, 1878).

3 INTRODUCTION Concept of seed physiological maturity
PM also permits the estimation of harvest maturity (2 weeks) after PM when the seed moisture content is low enough for temporary storage. Seed deterioration starts immediately after PM (Copeland and MacDonald, 1995). Figure 1. Seed and it’s relation to mother plant. Im- mature seed mature seed

4 INTRODUCTION Concept of seed physiological maturity
Figure 2. PM of Beans. PM Perdomo (1985) Seed Vigor Seed Dry Weight Seed Diameter Seed Moisture

5 INTRODUCTION Figure 3. Examples of maturity marker in sorghum, wheat and mung bean. Sorghum Wheat Mungbean PPT in seed development and maturation, mungbean

6 Physiological maturity-Maize
Formation of black layer Introduction and Objective Formation of black layer in the placental region of corn as they matures were referred by Johann, 1935. Kiesselbach and Walker, 1952 reported that the formation of black layer might serve as a reliable indicator of PM in corn. The study was conducted to explore such possibilities of formation of black layer as simple, practical, visual characteristic of maize seed as an accurate indicator of PM.

7 Physiological maturity-Maize
Formation of black layer Four hybrid varieties of different maturity levels were evaluated. Six plants per hybrids were selected for daily sampling of kernels. The sampling started at the approach of maturity as indicated by hardening of upper part of kernels and continued several days after the seed had reached it’s maximum dry weight. Each day 10 kernels were removed from a single kernel row in the middle of each ear.

8 Physiological maturity-Maize
Formation of black layer Two kernels per sample were cut lengthwise and development of black layer was examined and recorded. Figure 4. Length wise view for development of black layer in corn

9 Physiological maturity-Maize
Formation of black layer Figure 5. Basal view of black layer in corn with pedicel removed.

10 Physiological maturity-Maize
Formation of black layer Figure 6. Relationship between black layer formation and maximum kernel dry weights in corn Hybrids Maximum kernel dry weights (gm) Appearance of black layer (%) Sx48 49.2 51.7 XL45 56.0 55.7 SX29 58.3 56.7 3306 62.6 60.8 Black layer (%) Dry weights (gm) A close linear correlation was found among hybrids between black layer and maximum kernel dry weights. Maximum dry weight was attended when black layer formation was completed and no further weight increased was recorded.

11 Physiological maturity-Maize
Milk line as indicator of PM Introduction and Objective Black layer formation takes place within short time and causes inability to tell when it is formed. There is also variability in appearance consisting huge kernel moisture ranging from 15.4 to 75%. Thus, the study on milk line as indicator of PM was done to compare the reliability of kernel black layer formation and the disappearance of kernel milk as visual indicator of corn PM which can be monitored over a period of time. (Afuakwa and Crookston, 1984).

12 Physiological maturity-Maize
Milk line as indicator of PM Five hybrids were evaluated . Sampling consist of harvesting 10 consecutive ears from middle row were collected in soft dough stage, dented stage, half milk line stage, and every four days there after. Fresh weight, dry weight and moisture content were determined (following 5 days in a 60⁰C oven) .

13 Physiological maturity-Maize
Milk line as indicator of PM Ears were broken in the middle and position of milk lines were noted. Figure 7. Ears broken in the middle for milk line determination in corn Figure 8. A milk line appears across the kernel opposite the embryo side. This line advances down toward the cop with maturity and dried down.

14 Physiological maturity-Maize
Milk line as indicator of PM Figure 9. The position of milk line with different maturity level in corn The milk line disappears the corn becomes more solid as the grain matures. PM seed has no milk line

15 Physiological maturity-Maize
Milk line as indicator of PM Figure 10. Accumulation of kernel dry weight by pioneer ‘ 3978’ in 1980 and Various development stages of the kernels are identified according to the days after planting and they occurred. The stages are S- soft dough, D- dented, H- half milk ,P1- PM according to least square regression analysis, P2- Dunca’s Multiple Range test ,P3- PM by Polynomial regression analysis, NM- No milk line stage,BL- Black layer completely formed.

16 Physiological maturity-Maize
Result Black layer developed in all varieties. The relationship between maximum kernel dry weight and black layer formation was linear. Soft dough stage signaled the beginning of milk to solid convertion. Soon after fully dented stage, the milk line became visible on the kernel face opposite the germ and its progression could be monitored. Kernel moisture at the half milk line stage was 40%. Loss of all milk from kernel occurred an average of 2 days prior to black layer formation. Disappearance of milk line coincided with maximum kernel dry weight.

17 Physiological maturity-Maize
Discussion Under normal conditions both ( milk line and black layer formation) occurred simultaneously. But under stress condition black layer formation occurred while endosperm milk was still present. Black layer formation can be more reliable indicator of PM because of its consistence formation irrespective of environmental condition and grain moisture content because kernel don’t accumulate dry mater after black layer formation. Milk line is more useful in monitoring grain maturation prior to PM because it can be easily visible and monitored during the maturation period.

18 Physiological maturity-Soybean
Introduction and Objective Previous studies on soybean maturity was based on the loss of green color in the pod as indicator of PM (Crookstoon and Hill, 1978; Tekernoy et al., 1979). These studies were subjective and based on pods attached at specified nodes on the lower portion of the stem, thus the usefulness of their criteria for indicating PM of an entire soybean plant was not determined. The present study was therefore being done to determine if the loss of green color from pods was a reliable indicator of PM of an entire soybean plant or not. Gbikipi and Crookstoon, 1981

19 Physiological maturity-Soybean
Figure11. Soybean field at different maturity stages not mature PM HM

20 Physiological maturity-Soybean
Figure 12. Sequence of pod formation and seed filling

21 Physiological maturity-Soybean
Figure 13. Mature soybean plots PM HM

22 Physiological maturity-Soybean
Figure 14(a). The whole-plant dry weight (solid lines) and seed moisture content (dashed lines) of 4 soybean cultivars. Physiological maturity (PM) was determined as the intercept of a line representing mature seed weight and with a slope of the rate of seed weight increase. No Visual characters 1 Pod containing a green seed ( at one of the four uppermost nodes 2 One normal pod on the main stem that has reached it’s mature color 3 Pods free of green color 4 Leaves free of green color 5 Pods brown 6 Petioles free of green color 7 Stems free of green color 8 Leaves fallen

23 Physiological maturity-Soybean
Figure 14(b). Frequency of occurrences of criteria of 4 soybean cultivars over 2 years. (6) (6) No Visual characters 2 One normal pod on the main stem that has reached it’s mature color 3 Pods free of green color

24 Physiological maturity-Soybean
Figure 15. Soybean PM and visual marker of maturity

25 Physiological maturity-Soybean
Result Criteria no 3 ( pods free of green color) coincided with calculated PM most consistently. Criteria no 2 ( one normal pod on main stem that has reached its mature color) was useful predictor of the date of occurrence of PM. At PM the moisture content of individual seed was 55%. The average moisture content of all seed at PM was 44% due to different maturity timing ( difference of 11 days) Criteria no 4, 6, 7 and 8 occurred at variable time periods from the point of PM for each cultivar. Harvest maturity (13% MC) occurred 10 to 13 days after physiological maturity.

26 Physiological maturity-Soybean
Discussion Criteria no 3 ( pods free of green color) can be regarded as prediction of PM. The result also confirms the previous studies of loss of green color in pod as indicator of PM of entire soybean plant.

27 Seed maturity-Cabbage
Chlorophyll fluorescence of the testa Figure 17. Chlorophyll content of cabbage seed

28 Seed maturity-Cabbage
Chlorophyll fluorescence of the testa Figure 18. Seed quality and germination performances of cabbage seed

29 Seed maturity-Cabbage
Chlorophyll fluorescence of the testa Result and Discussion The germination performance was inversely related to the magnitude of the CF signal. The seeds from the subsample with the lowest CF signal germinated at 100% and had highest germination rate. The very high CF subsample had significantly reduced performance. It is useful as non-distructive marker of maturity and germination performance. It can be used in determining maturity and quality of all types of seeds for which the chlorophyll is broken down during the maturation process.

30 Physiological maturity-Sunflower
Introduction and Objective Several studies have been conducted in determining sunflower PM based on visual character (color) but they are subjective and may vary with environmental conditions. This visual character have not been validated in terms of maximum fruit dry weight. Studies on relationship of MC at PM of sunflower have also been done but there is no appropriate model that matches seed dry matter accumulation to seed MC. Therefore the study was conducted with the objectives of PM in sunflower coincides with fixed seed MC which coincides with maximum seed dry matter accumulation.

31 Physiological maturity-Sunflower
Influence of seed in capitulum in determining PM in Sunflower Figure 19. Flower arrangement and seed development in capitulum of sunflower Flowering begins at periphery and progress towards center. It takes 5-12 days depending on total no of floral circle and genotypes . PM at periphery Is earlier than center.

32 Physiological maturity-Sunflower
Plants were grown in different condition (open field and green house). Sampling began at flowering and continued 30 days after PM (when final seed weight did not increase). The seed were harvested at 2-3 days interval from peripheral and intermediate positions on capitulum. Fresh (seed weighed 3-5 minutes after harvest) and dry weight (48 h at 60 ⁰C) was determined.

33 Physiological maturity-Sunflower
Figure 21. Relative SDW and MC for peripheral seeds in 8 genotypes of sunflower. At moisture content 38⁰% all genotypes had maximum SDW which did not increase later.

34 Physiological maturity-Sunflower
Relationship of seed dry weight and water content in intermediate and peripheral seeds of 2 genotype sunflower Figure22. Dynamics of SDW (square) And MC (circles) between peripheral (closed symbols) and intermediate (open symbols) Seed at intermediate achieved lower SDW and reached PM later than fruit at peripheral. Seed at intermediate had greater MC than peripheral at all times.

35 Physiological maturity-Sunflower
Standardization of SDW and WC Figure 23 . Relative SDW and MC for peripheral and intermediate seed of 8 genotypes of sunflower At moisture content 38⁰% all genotypes had maximum SDW which did not increase later

36 Physiological maturity-Sunflower
Figure 25. Picture of mature sunflower Yellow back with bracts beginning turn brown, PM (38% MC) White seed Immature seed Gray seed mature seed

37 Physiological maturity-Sunflower
Result Seed MC of 38% proved strong indicator of PM. Seed from intermediate position in capitulum started growing 3-5 days later than peripheral seeds and matured 3-8 days later. At anthesis seed MC was 89% and dropped continuously during grain filling and post PM periods. Seed MC at intermediate was higher than peripheral at all time from start of anthesis.

38 Physiological maturity-Sunflower
Discussion Although there were difference in maturity level and SDW variation between intermediated and peripheral fruits but those were minimize by standardization using relative SDW of all genotypes. The relationship between Relative SDW and MC showed similar characteristic across position when fitted in tri-linear function. The work has been carried out in various conditions using all possible characteristic of sunflower development. Random sampling of grain at water concentration of 38% involved only a small yield penalty (<5%).

39 References Afuakwa, J. J. and R. K. Crookston usuing the kernel milk line to visually monitor grain maturity in maize.Crop Sci. 24: Crookston, R. K., and D. S. Hill A visual indicator of the physiological maturity of soybean seed. Crop Sci. 18: Daynard, T. B and W. G. Duncan The black layer and grain maturity in corn. Crop Sci. 9: Gbikpi, P.J. and R. K. Crookstoon A whole-plant indicator of soybean physiological maturity. Crop Sci. 21: Jalink , H., A. Frandas, R. Van Der Schoor, J.B. Bino Chlorophyll fluorescence of the testa of Brassica oleracea seeds as an indicator of seed maturity and seed quality. Sci. agris., Piracicaba, 55: Rondanini, D. P., R. Savin, and A. J. Hall Estimation of physiological maturity in sunflower as a function of fruit water concentration. Europ. J. Agronomy 26: TeKrony, D.M., D. B. Egli, J. Ballas, T. Pfeifferet, and R. J. Fellows Physiological maturity in soybean. Agron. J. 71:

40 Thanks for your attention!
Questions and comments are greatly appreciated!


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