Pollen viability, pollen amount and pollen shed dynamics are critical elements in wheat breeding. Changing environmental conditions like abiotic stress can alter these parameters. This can lead to a decrease of a successful pollination and consecutively lower the yield.
Male Line Characterization for Hybrid Seed Production
Hybrid wheat results from crosses between carefully selected inbread wheat lines. The challenge to produce hybrid wheat lies in the breeding and commercial multiplication of the hybrid parent seed. Wheat is a self-pollinated species, that naturally out-crosses rarely. For hybrid seed production cross pollination is mandatory and has to be performed on a large-scale
Therefore the selection of male lines that are capable of producing high pollen quality and quantity is crucial to ensure effective cross-pollination. Based on this information, the female to male ratio can be optimized.
Traditional pollen analysis methods are based on staining or germination. In the case of wheat, these methods can not be applied due to the short lifetime of wheat pollen and its sensitive behaviour in liquids, as the pollen grains tend to burst.
With the Ampha Z32 Pollen Analyzer, a reliable measurement of pollen viability and quantity is possible and you can:
Analyze Pollen Shedding Dynamics
A valid approach to select male lines that produce a large quantity of pollen is to quantify the pollen shed per area and time. With the Ampha Z32 Pollen Analyzer and liquid pollen traps you can analyze pollen shed dynamics during the flowering period.
Pollen Shed Experiment
In a field trial, the pollen shed of two different wheat varieties was quantified throughout one day.
The illustration shows a ten-hour pollen shed time-course in two-hour intervals. Grey dots are pollen counts from individual liquid traps in the same field. The data of two varieties measured on two different days is shown.
Pollen Trap Design
The picture shows a wheat pollen trap, consisting of a trap holder and a composite of liquid container, filter and funnel. The trap can be inserted in the holder and exchanged easily. The liquid is a specific buffer for counting pollen cells.
Quantify Wheat Pollen Shed Per Spike
Another approach to improve the female to male ratio is to quantify the pollen shed of a whole spike. This allows to quantify the amount of pollen of all spikelets as one additional parameter for the selection of the male line.
Pollen Quantity Per Spike & Variety
The illustration shows the quantification of pollen shed per spike. Grey dots are quantifications from individual spikes. The different colours represent different wheat varieties.
In order to determine the quantity of shed pollen from one spike, just before flowering the wheat spike was covered with a paper bag, as shown in the picture. After flowering was completed, the released pollen was collected and quantified.
Assess Wheat Pollen Lifetime After Shedding
Wheat pollen is very short-lived. For hybrid wheat breeding, a high viability and long lifetime are necessary, as the pollen travel from the male to the female plant. Assessing the viability of different lines is an effective tool to select parental lines with high pollen quality for breeding.
Pollen Lifetime Determination
The diagram shows the viability decrease of shed wheat pollen measured in 10 min intervals.
Identify Stress-Tolerance of Wheat Lines
Wheat pollen is very sensitive to abiotic stress. Especially during flowering, high temperatures can negatively affect pollen quality, resulting in a reduced seed set.
Monitoring of the effects of heat and drought on pollen development and mature pollen quality allows to select the most stress-tolerant lines for breeding.
Microspore Development in Wheat
Speed Up Plant Breeding With DH Plant Production
Doubled haploid (DH) plant production technique is an important system to
speed up plant breeding programs by drastically reducing the time period needed to develop new cultivars.
Amphasys offers a technology that makes the process of DH plant production more efficient. Save expensive resources by significantly increasing the number of measurements and enabling data-driven decision making.
The Ampha Z32 is a fast and reliable tool to:
Distinguish Different Microspore Stages
For DH production in wheat, microspores need to be extracted when they are in an early to mid-uninucleate stage.
With the Ampha Z32 Pollen Analyzer it is possible to monitor the microspore development from an early uninucleate state until pollen shedding. It is therefore possible to determine the right stage exactly and extract only the micropores in the early to mid-uninucleate stage.
Microspore Development in Wheat
The graph shows an overlay of various measurements. Microspores of spikelets in different development stages were measured. A shift on the y axis represents the growth in volume of a cell.
Identify Uninucleate Mircospores
To increase the efficiency in DH production it is crucial to work with microspores of the right developmental stage. The Ampha Z32 Pollen Analyzer allows to easily measure a large amount of samples with an easy sample preparation and analysis of thousands of cells in a few minutes: highly accurate and usable for routine applications.
The animation shows how clearly the individual developmental stages of the microspore development can be identified.
Understanding Heterogeneity of the Developmental Stages within the Spike and Spikelet
A spike and even a spikelet may contain a range of microspores at different developmental stages. For DH production in wheat, microspores need to be extracted when they are in an early to mid-uninucleate stage. The identification of the right developmental stage can be easily performed with the Ampha Z32 in such a way that a large amount of samples can be measured in short time, allowing a high efficiency and accuracy to speed up the breeding process.
Microspore Development within Single Spikes
The bar plot shows measurements of microspores of different spikelets of the same spike. The microspores of different spikelets are at different developmental stages and even one spikelet can contain microspores of various stages.