Presentation on theme: "IDENTIFICATION OF SPECIFIC VISIUAL INDICATORS OF SEED MATURITY"— Presentation transcript:
1 IDENTIFICATION OF SPECIFIC VISIUAL INDICATORS OF SEED MATURITY SURAJ CHHETRISCHOOL OF CROP PRODUCTION TECHNOLOGYSURANAREE UNIVERSITY OF TECHNOLOGY
2 INTRODUCTION Concept of physiological maturity PM is defined as occuring when the seed reaches its maximum dry weight, represent maximum viability and vigor.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.PM permits an accurate measure of the duration of the grain filling period.PM also permits the estimation of harvest time which usually is within two weeks after PM.
3 INTRODUCTION Concept of physiological maturity Figure 1. Seed and it’s relation to mother plantIm-mature seedmature seed
4 INTRODUCTION Concept of physiological maturity Figure 2. PM of Beans Perdomo (1985)Seed VigorSeed Dry WeightSeed DiameterSeed Moisture
5 INTRODUCTION Figure 3. Maturity marker Sorghum Wheat Mungbean WheatMungbeanPPT in seed development and maturation, mungbean
6 Physiological maturity-Maize Formation of black layerIntroduction and ObjectiveFormation of black layer in the placental region of corn as they matures were referred on the study of susceptibility of corn to kernel rots .Kiesselbach and Walker also suggested 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 layerFour 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 and frozen.
8 Physiological maturity-Maize Formation of black layerTwo 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
9 Physiological maturity-Maize Formation of black layerFigure 5. Basal view of black layer with pedicel removed
10 Physiological maturity-Maize Formation of black layerFigure 6. Relationship between black layer formation and maximum kerneldry weightsHybridsMaximum kernel dry weights (gm)Appearance of black layer (%)Sx4849.251.7XL4556.055.7SX2958.356.7330662.660.8A close linear correlation was found among hybridsbetween black layer and maximum kernel dry weights.
11 Physiological maturity-Maize Milk line as indicator of PMIntroduction and ObjectiveMany methods (grain moisture content, black layerformation, calendar days accumulation after silking) hadbeen used in predicting PM in maize.Kernel moisture cannot be visibly determined and requirestime to dry the grain.Black layer formation takes place very fast within 3 days andcauses inability to tell when it is formed, there is alsovariability in appearance consisting huge kernel moistureranging from 15.4 to 75%.Thus, the study on milk line as indicator of PM was done tofind out more reliable and visual indicator which can bemonitored over a period of time.
12 Physiological maturity-Maize Milk line as indicator of PMFive hybrids were evaluated .Samples (10 consecutive ears from middle row werecollected in soft dough stage, dented stage, half milk linestage, and every four days there after.Ears were broken in the middle and position of milk lineswere noted.Fresh weight, dry weight and moisture content were alsodetermined.
13 Physiological maturity-Maize Milk line as indicator of PMFigure 7. Ears broken in themiddle for milk line determinationFigure 8. A milk lineappears across thekernel opposite theembryo side. Thisline advances downtoward the cop withmaturity and dry down.
14 Physiological maturity-Maize Milk line as indicator of PMFigure 9. The position of milk line with different maturity levelThe milk line disappears( the corn becomes more solid) as the grain matures.No milk line
15 Physiological maturity-Maize Milk line as indicator of PMFigure 10. Accumulation of kernel dry weight.S- soft dough, D- dented, H- half milk ,P1- PM according to least square regression analysis, P2- Dunca’s Multiple Range testP3- PM by Polynomial regression analysis, NM- No milk line stageBL- Black layer completely formed.
16 Physiological maturity-Maize ResultBlack 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 conversation.Soon after fully dented stage, the milk line became externally 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 DiscussionThere is a contrast report on formation of black layer with regard to moisture content (45% MC in cool autumn temperatures , 15.4% and 16.8% MC in two of in-breds and even 75% MC in one report).However in the present study under normal conditions both 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.
18 Physiological maturity-Maize DiscussionMilk line is more useful in monitoring grain maturation prior to PM because it can be easily visible and monitored during the maturation period.Half milk line stage can be used in pre-harvest planning purposes since it indicated that kernel contained 40% moisture and were 2 to 3 weeks from harvest.
19 Physiological maturity-Soybean Introduction and ObjectivePrevious studies on soybean maturity was based on the loss of green color in the pod as indicator of PM.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.To relate disappearance of green pod color to the occurrence of other estimates already in use or describe in literature.
20 Physiological maturity-Soybean Figure11. Soybean field at different maturity stagenot maturePMHM
22 Physiological maturity-Soybean Figure 13. Sequence of pod formation and seed filling
23 Physiological maturity-Soybean Figure 14(a). The whole-plant dry weight (Solid lines) and seed moisture content (dashed lines) of 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.NoVisual characters1Pod containg a green seed2One normal pod on the main stem that has reached it’s mature color3Pods free of green color4Leaves free of green color5Pods brown6Petioles free of green color7Stems free of green color8Leaves fallen
24 Physiological maturity-Soybean Figure 14(b).(6)(6)NoVisual characters2One normal pod on the main stem that has reached it’s mature color3Pods free of green color
26 Physiological maturity-Soybean ResultCriteria 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 P.M was 44% due to different maturity timing ( difference of 11 days)Criteria no 4,6,7,8 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.
27 Physiological maturity-Soybean DiscussionCriteria 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.The experiment is good, as it can be practically used in the field.
28 Seed maturity-Cabbage Chlorophyll fluorescence of the testaIntroduction and ObjectiveImmature seed contains high amount of chlorophyll.The chlorophyll content is broken down during the late stages of ripening process.Chlorophyll in the seed do not show variable fluorescence because the metabolism of the seed has stopped at the moment of acquisition of desiccation tolerance.Studies using CF have been conducted in beans, carrot, turnip and other crops for determining seed maturity and its effect in germination and storability.Such study was undertaken in cabbage to introduce a non-destructive and instantaneous method for determining the maturity and quality of Individual seed.
29 Seed maturity-Cabbage Chlorophyll fluorescence of the testaFigure 16. Schematic representation of the set up used for CF measurement.Chlorophyll a in the seed coat was excited by laser radiation (656 nm) and the resulting fluorescence filter 730 nm, than pass to lock- in Amplifier for measurement.
30 Seed maturity-Cabbage Chlorophyll fluorescence of the testaBased on the magnitude of CF signal, four subsamples weremade-Low.Medium .High .Very high.The seeds after separation into subsamples were subjected for germination test as per ISTA, 1996.
31 Seed maturity-Cabbage Chlorophyll fluorescence of the testaFigure 17. chlorophyll content of seedradio.weblogs.com/.../221205_cabbage_seed.jpg
32 Seed maturity-Cabbage Chlorophyll fluorescence of the testaFigure 18. Different sub samples and germination performances
33 Seed maturity-Cabbage Chlorophyll fluorescence of the testaResult and DiscussionThe 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% with 100% normal seedlings 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.
34 Physiological maturity-Sunflower Introduction and ObjectiveSeveral studies have been conducted in determiningsunflower PM based on visual character (color) but they aresubjective and may vary with environmental conditions.This visual character have not been validated in terms ofmaximum fruit dry weight.Studies on relationship of MC at PM of sunflower have alsobeen done but there is no appropriate model that matchesfruit dry matter accumulation to fruit WC valid acrossdifferent genotypes and growing conditions.There is no consensus about the effects of stress on grainWC at PM, although there has been report earlier that briefexposure to various types of stress have shown to altergrain growth dynamics.
35 Physiological maturity-Sunflower Introduction and ObjectiveTherefore the study was conducted with the objectives ofPM in sunflower coincides with fixed fruit WC whichcoincides with maximum fruit dry matter accumulation andto study the effect of brief exposure to high temperaturestress on grain dry weight and fruit WC.
36 Physiological maturity-Sunflower Influence of fruit in capitulum in determining PMFigure 19. Flower arrangement and seed development in capitulumFlowering 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.waynesword.palomar.edu/images/capitul2.gif
37 Physiological maturity-Sunflower Plants were grown in different condition (open field andgreen house).Sampling began at flowering and continued 30 days afterPM (when final fruit weight did not increase).The fruit were harvested at 2-3 days interval fromperipheral and intermediate positions on capitulum.Fresh (fruits weighed 3-5 minutes after harvest) and dryweight (48 h at 60 ⁰C) was determined.Fruit water content was calculated as the differencebetween fresh and dry weight and Fruit waterconcentration as the ratio between fruit water contentand fresh weight expressed as percentage.
38 Physiological maturity-Sunflower Figure 20. Relationship between FDW and WC (triangles) during grain filling corresponding toperipheral fruits.The breakpoint between second and third section (equivalent to fruit WC at PM)did not differ between genotypes.Differences in FDW wasobserved between genotypes.Except HA89 other genotypesShowed similar fruit WC. ThisMay be due to different fruitsize, proportion of pericarp inThe fruit.
39 Physiological maturity-Sunflower Figure 21. Relative FDW and WC for peripheral fruitsAt moisture content 38⁰C all genotypes had maximumFDW which did not increase later.
40 Physiological maturity-Sunflower Determination of fruit dry weight and water concentration dynamics in intermediate fruitsFigure22. Dynamics of FDW (square)and WC (circles) between peripheral(closed symbols) and intermediate(open symbols)Fruit at intermediate achieved lower FDW and reached PM later than fruit at peripheral.Fruit at intermediate had greater WC than peripheral at all times.
41 Physiological maturity-Sunflower Standardization of FDW and fruit WCFigure 23 . Relative FDW and WC for peripheral and intermediate fruitsAt moisture content 38⁰C all genotypes had maximum FDW which did not increase later
42 Physiological maturity-Sunflower Figure 24 . Dynamics of fruit growth and fruit WC at PM exposed to high temperature.
43 Physiological maturity-Sunflower Figure 25. Picture of mature sunflowerYellow back with bracts beginning turn brown, PMWhite seedImmature seedGray seedmature seed
44 Physiological maturity-Sunflower ResultFruit WC of 38% proved robust indicator of PM except forHA89 genotype.Fruit from intermediate position in capitulum startedgrowing 3-5 days later than peripheral fruits and matured3-8 days later.At anthesis fruit WC was 89% and dropped continuouslyduring grain filling and post PM periods.The Fruit WC at intermediate was higher than peripheral atall time from start of anthesis.Exposure to stress condition like high temperatureshortened grain filling duration by 2-4 days, decreased finalfruit weight and increased fruit WC at P.M.
45 Physiological maturity-Sunflower DiscussionAlthough there were difference in maturity level and FDWvariation between intermediated and peripheral fruits butthose were minimize by standardization using relative FDWof all genotypes.The relationship between Relative FDW and WC showedsimilar characteristic across position when fitted in tri-linearfunction.The work has been carried out in various conditions usingall possible characteristic of sunflower development suchas study on both peripheral and intermediate fruit maturityand in stress and non-stress condition.
46 Physiological maturity-Sunflower DiscussionRandom sampling of grain at water concentration of 38%involved only a small yield penalty (<5%) in both stress andunstressed condition.All genotypes except HA89 attained maximum fruit dryweight at water concentration 38%.The reason for variation in fruit moisture concentration inHA89 genotype is not clearly mention, it may be due to fruitsize, propotion of pericarp in the fruit.
47 ReferencesAfuakwa, 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 physiologicalmaturity 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:
48 Thanks for your attention! Questions and comments are greatly appreciated!